http://scons.tigris.org/issues/show_bug.cgi?id=2345
[scons.git] / src / engine / SCons / BuilderTests.py
index fbf79f43b687c706deedfd170366cca94a637f2e..50cf778839e3245c8395337277e7fdc55206cb9f 100644 (file)
@@ -23,6 +23,8 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.compat
+
 # Define a null function for use as a builder action.
 # Where this is defined in the file seems to affect its
 # byte-code contents, so try to minimize changes by
@@ -30,11 +32,12 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 def Func():
     pass
 
+import collections
+import io
 import os.path
+import re
 import sys
-import types
 import unittest
-import UserList
 
 import TestCmd
 
@@ -42,6 +45,10 @@ import SCons.Action
 import SCons.Builder
 import SCons.Environment
 import SCons.Errors
+import SCons.Subst
+import SCons.Util
+
+sys.stdout = io.StringIO()
 
 # Initial setup of the common environment for all tests,
 # a temporary working directory containing a
@@ -79,23 +86,17 @@ class Environment:
     def subst(self, s):
         if not SCons.Util.is_String(s):
             return s
-        try:
-            if s[0] == '$':
-                return self.d.get(s[1:], '')
-            if s[1] == '$':
-                return s[0] + self.d.get(s[2:], '')
-        except IndexError:
-            pass
-        return self.d.get(s, s)
+        def substitute(m, d=self.d):
+            return d.get(m.group(1), '')
+        return re.sub(r'\$(\w+)', substitute, s)
     def subst_target_source(self, string, raw=0, target=None,
                             source=None, dict=None, conv=None):
-        return SCons.Util.scons_subst(string, self, raw, target,
-                                      source, dict, conv)
-    def subst_list(self, string, raw=0, target=None,
-                   source=None, dict=None, conv=None):
-        return SCons.Util.scons_subst_list(string, self, raw, target,
-                                           source, dict, conv)
-    def arg2nodes(self, args, factory):
+        return SCons.Subst.scons_subst(string, self, raw, target,
+                                       source, dict, conv)
+    def subst_list(self, string, raw=0, target=None, source=None, conv=None):
+        return SCons.Subst.scons_subst_list(string, self, raw, target,
+                                            source, {}, {}, conv)
+    def arg2nodes(self, args, factory, **kw):
         global env_arg2nodes_called
         env_arg2nodes_called = 1
         if not SCons.Util.is_List(args):
@@ -103,7 +104,7 @@ class Environment:
         list = []
         for a in args:
             if SCons.Util.is_String(a):
-                a = factory(a)
+                a = factory(self.subst(a))
             list.append(a)
         return list
     def get_factory(self, factory):
@@ -118,14 +119,16 @@ class Environment:
         self.d[item] = var
     def __getitem__(self, item):
         return self.d[item]
+    def __contains__(self, item):
+        return self.d.__contains__(item)
     def has_key(self, item):
-        return self.d.has_key(item)
+        return item in self.d
     def keys(self):
         return self.d.keys()
     def get(self, key, value=None):
         return self.d.get(key, value)
     def Override(self, overrides):
-        env = apply(Environment, (), self.d)
+        env = Environment(**self.d)
         env.d.update(overrides)
         env.scanner = self.scanner
         return env
@@ -144,6 +147,14 @@ class Environment:
     def __cmp__(self, other):
         return cmp(self.scanner, other.scanner) or cmp(self.d, other.d)
 
+class MyAction:
+    def __init__(self, action):
+        self.action = action
+    def __call__(self, *args, **kw):
+        pass
+    def get_executor(self, env, overrides, tlist, slist, executor_kw):
+        return ['executor'] + [self.action]
+
 class MyNode_without_target_from_source:
     def __init__(self, name):
         self.name = name
@@ -151,6 +162,9 @@ class MyNode_without_target_from_source:
         self.builder = None
         self.is_explicit = None
         self.side_effect = 0
+        self.suffix = os.path.splitext(name)[1]
+    def disambiguate(self):
+        return self
     def __str__(self):
         return self.name
     def builder_set(self, builder):
@@ -239,12 +253,12 @@ class BuilderTestCase(unittest.TestCase):
         assert not hasattr(n2, 'env')
 
         l = [1]
-        ul = UserList.UserList([2])
+        ul = collections.UserList([2])
         try:
             l.extend(ul)
         except TypeError:
             def mystr(l):
-                return str(map(str, l))
+                return str(list(map(str, l)))
         else:
             mystr = str
 
@@ -253,14 +267,14 @@ class BuilderTestCase(unittest.TestCase):
         tlist = builder(env, target = [nnn1, nnn2], source = [])
         s = mystr(tlist)
         assert s == "['nnn1', 'nnn2']", s
-        l = map(str, tlist)
+        l = list(map(str, tlist))
         assert l == ['nnn1', 'nnn2'], l
 
         tlist = builder(env, target = 'n3', source = 'n4')
         s = mystr(tlist)
         assert s == "['n3']", s
         target = tlist[0]
-        l = map(str, tlist)
+        l = list(map(str, tlist))
         assert l == ['n3'], l
         assert target.name == 'n3'
         assert target.sources[0].name == 'n4'
@@ -268,7 +282,7 @@ class BuilderTestCase(unittest.TestCase):
         tlist = builder(env, target = 'n4 n5', source = ['n6 n7'])
         s = mystr(tlist)
         assert s == "['n4 n5']", s
-        l = map(str, tlist)
+        l = list(map(str, tlist))
         assert l == ['n4 n5'], l
         target = tlist[0]
         assert target.name == 'n4 n5'
@@ -277,7 +291,7 @@ class BuilderTestCase(unittest.TestCase):
         tlist = builder(env, target = ['n8 n9'], source = 'n10 n11')
         s = mystr(tlist)
         assert s == "['n8 n9']", s
-        l = map(str, tlist)
+        l = list(map(str, tlist))
         assert l == ['n8 n9'], l
         target = tlist[0]
         assert target.name == 'n8 n9'
@@ -291,7 +305,8 @@ class BuilderTestCase(unittest.TestCase):
         #be = target.get_build_env()
         #assert be['VAR'] == 'foo', be['VAR']
 
-        if not hasattr(types, 'UnicodeType'):
+        try: unicode
+        except NameError:
             uni = str
         else:
             uni = unicode
@@ -329,7 +344,12 @@ class BuilderTestCase(unittest.TestCase):
         except SCons.Errors.UserError, e:
             pass
         else:
-            raise "Did not catch expected UserError."
+            raise Exception("Did not catch expected UserError.")
+
+        builder = SCons.Builder.Builder(action="foo")
+        target = builder(env, None, source='n22', srcdir='src_dir')[0]
+        p = target.sources[0].path
+        assert p == os.path.join('src_dir', 'n22'), p
 
     def test_mistaken_variables(self):
         """Test keyword arguments that are often mistakes
@@ -386,6 +406,10 @@ class BuilderTestCase(unittest.TestCase):
         builder = SCons.Builder.Builder(generator=generator)
         assert builder.action.generator == generator
 
+    def test_get_name(self):
+        """Test the get_name() method
+        """
+
     def test_cmp(self):
         """Test simple comparisons of Builder objects
         """
@@ -507,6 +531,22 @@ class BuilderTestCase(unittest.TestCase):
         tgt = builder(my_env, target = None, source = 'f6.zzz')[0]
         assert tgt.path == 'emit-f6', tgt.path
 
+    def test_set_suffix(self):
+        """Test the set_suffix() method"""
+        b = SCons.Builder.Builder(action='')
+        env = Environment(XSUFFIX = '.x')
+
+        s = b.get_suffix(env)
+        assert s == '', s
+
+        b.set_suffix('.foo')
+        s = b.get_suffix(env)
+        assert s == '.foo', s
+
+        b.set_suffix('$XSUFFIX')
+        s = b.get_suffix(env)
+        assert s == '.x', s
+
     def test_src_suffix(self):
         """Test Builder creation with a specified source file suffix
         
@@ -528,11 +568,11 @@ class BuilderTestCase(unittest.TestCase):
                 "Unexpected tgt.sources[0] name: %s" % tgt.sources[0].path
 
         b2 = SCons.Builder.Builder(src_suffix = '.2', src_builder = b1)
-        assert b2.src_suffixes(env) == ['.2', '.c'], b2.src_suffixes(env)
+        r = sorted(b2.src_suffixes(env))
+        assert r == ['.2', '.c'], r
 
         b3 = SCons.Builder.Builder(action = {'.3a' : '', '.3b' : ''})
-        s = b3.src_suffixes(env)
-        s.sort()
+        s = sorted(b3.src_suffixes(env))
         assert s == ['.3a', '.3b'], s
 
         b4 = SCons.Builder.Builder(src_suffix = '$XSUFFIX')
@@ -568,6 +608,21 @@ class BuilderTestCase(unittest.TestCase):
         tgt = b9(env, target=None, source='foo_altsrc.b')
         assert str(tgt[0]) == 'foo.c', str(tgt[0])
 
+    def test_src_suffix_expansion(self):
+        """Test handling source suffixes when an expansion is involved"""
+        env = Environment(OBJSUFFIX = '.obj')
+
+        b1 = SCons.Builder.Builder(action = '',
+                                   src_suffix='.c',
+                                   suffix='.obj')
+        b2 = SCons.Builder.Builder(action = '',
+                                   src_builder=b1,
+                                   src_suffix='.obj',
+                                   suffix='.exe')
+        tgt = b2(env, target=None, source=['foo$OBJSUFFIX'])
+        s = list(map(str, tgt[0].sources))
+        assert s == ['foo.obj'], s
+
     def test_suffix(self):
         """Test Builder creation with a specified target suffix
 
@@ -637,14 +692,35 @@ class BuilderTestCase(unittest.TestCase):
                                         single_source = 1, suffix='.out')
         env['CNT'] = [0]
         tgt = builder(env, target=outfiles[0], source=infiles[0])[0]
+        s = str(tgt)
+        t = os.path.normcase(test.workpath('0.out'))
+        assert os.path.normcase(s) == t, s
         tgt.prepare()
         tgt.build()
         assert env['CNT'][0] == 1, env['CNT'][0]
         tgt = builder(env, outfiles[1], infiles[1])[0]
+        s = str(tgt)
+        t = os.path.normcase(test.workpath('1.out'))
+        assert os.path.normcase(s) == t, s
         tgt.prepare()
         tgt.build()
         assert env['CNT'][0] == 2
         tgts = builder(env, None, infiles[2:4])
+        try:
+            [].extend(collections.UserList())
+        except TypeError:
+            # Old Python version (1.5.2) that can't handle extending
+            # a list with list-like objects.  That means the return
+            # value from the builder call is a real list with Nodes,
+            # and doesn't have a __str__() method that stringifies
+            # the individual elements.  Since we're gong to drop 1.5.2
+            # support anyway, don't bother trying to test for it.
+            pass
+        else:
+            s = list(map(str, tgts))
+            expect = [test.workpath('2.out'), test.workpath('3.out')]
+            expect = list(map(os.path.normcase, expect))
+            assert list(map(os.path.normcase, s)) == expect, s
         for t in tgts: t.prepare()
         tgts[0].build()
         tgts[1].build()
@@ -664,13 +740,13 @@ class BuilderTestCase(unittest.TestCase):
             assert 0
         
         
-    def test_ListBuilder(self):
-        """Testing ListBuilder class."""
+    def test_lists(self):
+        """Testing handling lists of targets and source"""
         def function2(target, source, env, tlist = [outfile, outfile2], **kw):
             for t in target:
                 open(str(t), 'w').write("function2\n")
             for t in tlist:
-                if not t in map(str, target):
+                if not t in list(map(str, target)):
                     open(t, 'w').write("function2\n")
             return 1
 
@@ -699,7 +775,7 @@ class BuilderTestCase(unittest.TestCase):
             for t in target:
                 open(str(t), 'w').write("function3\n")
             for t in tlist:
-                if not t in map(str, target):
+                if not t in list(map(str, target)):
                     open(t, 'w').write("function3\n")
             return 1
 
@@ -718,195 +794,61 @@ class BuilderTestCase(unittest.TestCase):
         assert os.path.exists(test.workpath('sub1'))
         assert os.path.exists(test.workpath('sub2'))
 
-    def test_MultiStepBuilder(self):
-        """Testing MultiStepBuilder class."""
+    def test_src_builder(self):
+        """Testing Builders with src_builder"""
+        # These used to be MultiStepBuilder objects until we
+        # eliminated it as a separate class
         env = Environment()
         builder1 = SCons.Builder.Builder(action='foo',
                                          src_suffix='.bar',
                                          suffix='.foo')
-        builder2 = SCons.Builder.MultiStepBuilder(action='bar',
-                                                  src_builder = builder1,
-                                                  src_suffix = '.foo')
+        builder2 = SCons.Builder.Builder(action=MyAction('act'),
+                                         src_builder = builder1,
+                                         src_suffix = '.foo')
 
         tgt = builder2(env, source=[])
         assert tgt == [], tgt
 
-        tgt = builder2(env, target='baz',
-                       source=['test.bar', 'test2.foo', 'test3.txt'])[0]
-        assert str(tgt.sources[0]) == 'test.foo', str(tgt.sources[0])
-        assert str(tgt.sources[0].sources[0]) == 'test.bar', \
-               str(tgt.sources[0].sources[0])
-        assert str(tgt.sources[1]) == 'test2.foo', str(tgt.sources[1])
-        assert str(tgt.sources[2]) == 'test3.txt', str(tgt.sources[2])
+        sources = ['test.bar', 'test2.foo', 'test3.txt', 'test4']
+        tgt = builder2(env, target='baz', source=sources)[0]
+        s = str(tgt)
+        assert s == 'baz', s
+        s = list(map(str, tgt.sources))
+        assert s == ['test.foo', 'test2.foo', 'test3.txt', 'test4.foo'], s
+        s = list(map(str, tgt.sources[0].sources))
+        assert s == ['test.bar'], s
 
         tgt = builder2(env, None, 'aaa.bar')[0]
-        assert str(tgt) == 'aaa', str(tgt)
-        assert str(tgt.sources[0]) == 'aaa.foo', str(tgt.sources[0])
-        assert str(tgt.sources[0].sources[0]) == 'aaa.bar', \
-               str(tgt.sources[0].sources[0])
+        s = str(tgt)
+        assert s == 'aaa', s
+        s = list(map(str, tgt.sources))
+        assert s == ['aaa.foo'], s
+        s = list(map(str, tgt.sources[0].sources))
+        assert s == ['aaa.bar'], s
 
-        builder3 = SCons.Builder.MultiStepBuilder(action = 'foo',
-                                                  src_builder = 'xyzzy',
-                                                  src_suffix = '.xyzzy')
-        assert builder3.get_src_builders(Environment()) == []
+        builder3 = SCons.Builder.Builder(action='bld3')
+        assert not builder3.src_builder is builder1.src_builder
 
         builder4 = SCons.Builder.Builder(action='bld4',
                                          src_suffix='.i',
                                          suffix='_wrap.c')
-        builder5 = SCons.Builder.MultiStepBuilder(action='bld5',
-                                                  src_builder=builder4,
-                                                  suffix='.obj',
-                                                  src_suffix='.c')
-        builder6 = SCons.Builder.MultiStepBuilder(action='bld6',
-                                                  src_builder=builder5,
-                                                  suffix='.exe',
-                                                  src_suffix='.obj')
+        builder5 = SCons.Builder.Builder(action=MyAction('act'),
+                                         src_builder=builder4,
+                                         suffix='.obj',
+                                         src_suffix='.c')
+        builder6 = SCons.Builder.Builder(action=MyAction('act'),
+                                         src_builder=builder5,
+                                         suffix='.exe',
+                                         src_suffix='.obj')
         tgt = builder6(env, 'test', 'test.i')[0]
-        assert str(tgt) == 'test.exe', str(tgt)
-        assert str(tgt.sources[0]) == 'test_wrap.obj', str(tgt.sources[0])
-        assert str(tgt.sources[0].sources[0]) == 'test_wrap.c', \
-               str(tgt.sources[0].sources[0])
-        assert str(tgt.sources[0].sources[0].sources[0]) == 'test.i', \
-               str(tgt.sources[0].sources[0].sources[0])
-        
-    def test_CompositeBuilder(self):
-        """Testing CompositeBuilder class."""
-        def func_action(target, source, env):
-            return 0
-        
-        env = Environment(BAR_SUFFIX = '.BAR2', FOO_SUFFIX = '.FOO2')
-        builder = SCons.Builder.Builder(action={ '.foo' : func_action,
-                                                 '.bar' : func_action,
-                                                 '$BAR_SUFFIX' : func_action,
-                                                 '$FOO_SUFFIX' : func_action })
-
-        tgt = builder(env, source=[])
-        assert tgt == [], tgt
-        
-        assert isinstance(builder, SCons.Builder.CompositeBuilder)
-        assert isinstance(builder.action, SCons.Action.CommandGeneratorAction)
-
-        tgt = builder(env, target='test1', source='test1.foo')[0]
-        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
-        assert tgt.builder.action is builder.action
-
-        tgt = builder(env, target='test2', source='test1.bar')[0]
-        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
-        assert tgt.builder.action is builder.action
-
-        flag = 0
-        tgt = builder(env, target='test3', source=['test2.bar', 'test1.foo'])[0]
-        try:
-            tgt.build()
-        except SCons.Errors.UserError, e:
-            flag = 1
-        assert flag, "UserError should be thrown when we build targets with files of different suffixes."
-        match = str(e) == "While building `['test3']' from `test1.foo': Cannot build multiple sources with different extensions: .bar, .foo"
-        assert match, e
-
-        tgt = builder(env, target='test4', source=['test4.BAR2'])[0]
-        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
-        try:
-            tgt.build()
-            flag = 1
-        except SCons.Errors.UserError, e:
-            print e
-            flag = 0
-        assert flag, "It should be possible to define actions in composite builders using variables."
-        env['FOO_SUFFIX'] = '.BAR2'
-        builder.add_action('$NEW_SUFFIX', func_action)
-        flag = 0
-        tgt = builder(env, target='test5', source=['test5.BAR2'])[0]
-        try:
-            tgt.build()
-        except SCons.Errors.UserError:
-            flag = 1
-        assert flag, "UserError should be thrown when we build targets with ambigous suffixes."
-        del env.d['FOO_SUFFIX']
-        del env.d['BAR_SUFFIX']
-
-        foo_bld = SCons.Builder.Builder(action = 'a-foo',
-                                        src_suffix = '.ina',
-                                        suffix = '.foo')
-        assert isinstance(foo_bld, SCons.Builder.BuilderBase)
-        builder = SCons.Builder.Builder(action = { '.foo' : 'foo',
-                                                   '.bar' : 'bar' },
-                                        src_builder = foo_bld)
-        assert isinstance(builder, SCons.Builder.CompositeBuilder)
-        assert isinstance(builder.action, SCons.Action.CommandGeneratorAction)
-
-        tgt = builder(env, target='t1', source='t1a.ina t1b.ina')[0]
-        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
-
-        tgt = builder(env, target='t2', source='t2a.foo t2b.ina')[0]
-        assert isinstance(tgt.builder, SCons.Builder.MultiStepBuilder), tgt.builder.__dict__
-
-        bar_bld = SCons.Builder.Builder(action = 'a-bar',
-                                        src_suffix = '.inb',
-                                        suffix = '.bar')
-        assert isinstance(bar_bld, SCons.Builder.BuilderBase)
-        builder = SCons.Builder.Builder(action = { '.foo' : 'foo'},
-                                        src_builder = [foo_bld, bar_bld])
-        assert isinstance(builder, SCons.Builder.CompositeBuilder)
-        assert isinstance(builder.action, SCons.Action.CommandGeneratorAction)
-
-        builder.add_action('.bar', 'bar')
-
-        tgt = builder(env, target='t3-foo', source='t3a.foo t3b.ina')[0]
-        assert isinstance(tgt.builder, SCons.Builder.MultiStepBuilder)
-
-        tgt = builder(env, target='t3-bar', source='t3a.bar t3b.inb')[0]
-        assert isinstance(tgt.builder, SCons.Builder.MultiStepBuilder)
-
-        flag = 0
-        tgt = builder(env, target='t5', source=['test5a.foo', 'test5b.inb'])[0]
-        try:
-            tgt.build()
-        except SCons.Errors.UserError, e:
-            flag = 1
-        assert flag, "UserError should be thrown when we build targets with files of different suffixes."
-        match = str(e) == "While building `['t5']' from `test5b.bar': Cannot build multiple sources with different extensions: .foo, .bar"
-        assert match, e
-
-        flag = 0
-        tgt = builder(env, target='t6', source=['test6a.bar', 'test6b.ina'])[0]
-        try:
-            tgt.build()
-        except SCons.Errors.UserError, e:
-            flag = 1
-        assert flag, "UserError should be thrown when we build targets with files of different suffixes."
-        match = str(e) == "While building `['t6']' from `test6b.foo': Cannot build multiple sources with different extensions: .bar, .foo"
-        assert match, e
-
-        flag = 0
-        tgt = builder(env, target='t4', source=['test4a.ina', 'test4b.inb'])[0]
-        try:
-            tgt.build()
-        except SCons.Errors.UserError, e:
-            flag = 1
-        assert flag, "UserError should be thrown when we build targets with files of different suffixes."
-        match = str(e) == "While building `['t4']' from `test4b.bar': Cannot build multiple sources with different extensions: .foo, .bar"
-        assert match, e
-
-        flag = 0
-        tgt = builder(env, target='t7', source=['test7'])[0]
-        try:
-            tgt.build()
-        except SCons.Errors.UserError, e:
-            flag = 1
-        assert flag, "UserError should be thrown when we build targets with files of different suffixes."
-        match = str(e) == "While building `['t7']': Cannot deduce file extension from source files: ['test7']"
-        assert match, e
-
-        flag = 0
-        tgt = builder(env, target='t8', source=['test8.unknown'])[0]
-        try:
-            tgt.build()
-        except SCons.Errors.UserError, e:
-            flag = 1
-        assert flag, "UserError should be thrown when we build targets with files of different suffixes."
-        match = str(e) == "While building `['t8']': Don't know how to build a file with suffix `.unknown'."
-        assert match, e
+        s = str(tgt)
+        assert s == 'test.exe', s
+        s = list(map(str, tgt.sources))
+        assert s == ['test_wrap.obj'], s
+        s = list(map(str, tgt.sources[0].sources))
+        assert s == ['test_wrap.c'], s
+        s = list(map(str, tgt.sources[0].sources[0].sources))
+        assert s == ['test.i'], s
 
     def test_target_scanner(self):
         """Testing ability to set target and source scanners through a builder."""
@@ -942,7 +884,7 @@ class BuilderTestCase(unittest.TestCase):
         def func(self):
             pass
         
-        scanner = SCons.Scanner.Scanner(func, name='fooscan')
+        scanner = SCons.Scanner.Base(func, name='fooscan')
 
         b1 = SCons.Builder.Builder(action='bld', target_scanner=scanner)
         b2 = SCons.Builder.Builder(action='bld', target_scanner=scanner)
@@ -977,7 +919,8 @@ class BuilderTestCase(unittest.TestCase):
         assert tgt.builder.source_scanner is None, tgt.builder.source_scanner
         assert tgt.get_source_scanner(bar_y) is None, tgt.get_source_scanner(bar_y)
         assert not src.has_builder(), src.has_builder()
-        assert src.get_source_scanner(bar_y) is None, src.get_source_scanner(bar_y)
+        s = src.get_source_scanner(bar_y)
+        assert isinstance(s, SCons.Util.Null), repr(s)
 
         # An Environment that has suffix-specified SCANNERS should
         # provide a source scanner to the target.
@@ -1004,7 +947,8 @@ class BuilderTestCase(unittest.TestCase):
         assert tgt.get_source_scanner(bar_y), tgt.get_source_scanner(bar_y)
         assert str(tgt.get_source_scanner(bar_y)) == 'EnvTestScanner', tgt.get_source_scanner(bar_y)
         assert not src.has_builder(), src.has_builder()
-        assert src.get_source_scanner(bar_y) is None, src.get_source_scanner(bar_y)
+        s = src.get_source_scanner(bar_y)
+        assert isinstance(s, SCons.Util.Null), repr(s)
 
         # Can't simply specify the scanner as a builder argument; it's
         # global to all invocations of this builder.
@@ -1015,7 +959,8 @@ class BuilderTestCase(unittest.TestCase):
         assert tgt.get_source_scanner(bar_y), tgt.get_source_scanner(bar_y)
         assert str(tgt.get_source_scanner(bar_y)) == 'EnvTestScanner', tgt.get_source_scanner(bar_y)
         assert not src.has_builder(), src.has_builder()
-        assert src.get_source_scanner(bar_y) is None, src.get_source_scanner(bar_y)
+        s = src.get_source_scanner(bar_y)
+        assert isinstance(s, SCons.Util.Null), s
 
         # Now use a builder that actually has scanners and ensure that
         # the target is set accordingly (using the specified scanner
@@ -1033,7 +978,8 @@ class BuilderTestCase(unittest.TestCase):
         assert tgt.get_source_scanner(bar_y) == scanner, tgt.get_source_scanner(bar_y)
         assert str(tgt.get_source_scanner(bar_y)) == 'TestScanner', tgt.get_source_scanner(bar_y)
         assert not src.has_builder(), src.has_builder()
-        assert src.get_source_scanner(bar_y) is None, src.get_source_scanner(bar_y)
+        s = src.get_source_scanner(bar_y)
+        assert isinstance(s, SCons.Util.Null), s
 
 
 
@@ -1045,8 +991,8 @@ class BuilderTestCase(unittest.TestCase):
         forms of component specifications."""
 
         builder = SCons.Builder.Builder()
-
         env = Environment(BUILDERS={'Bld':builder})
+
         r = builder.get_name(env)
         assert r == 'Bld', r
         r = builder.get_prefix(env)
@@ -1057,27 +1003,36 @@ class BuilderTestCase(unittest.TestCase):
         assert r == '', r
         r = builder.src_suffixes(env)
         assert r == [], r
-        r = builder.targets('foo')
-        assert r == ['foo'], r
 
         # src_suffix can be a single string or a list of strings
+        # src_suffixes() caches its return value, so we use a new
+        # Builder each time we do any of these tests
 
-        builder.set_src_suffix('.foo')
-        r = builder.get_src_suffix(env)
+        bld = SCons.Builder.Builder()
+        env = Environment(BUILDERS={'Bld':bld})
+
+        bld.set_src_suffix('.foo')
+        r = bld.get_src_suffix(env)
         assert r == '.foo', r
-        r = builder.src_suffixes(env)
+        r = bld.src_suffixes(env)
         assert r == ['.foo'], r
 
-        builder.set_src_suffix(['.foo', '.bar'])
-        r = builder.get_src_suffix(env)
+        bld = SCons.Builder.Builder()
+        env = Environment(BUILDERS={'Bld':bld})
+
+        bld.set_src_suffix(['.foo', '.bar'])
+        r = bld.get_src_suffix(env)
         assert r == '.foo', r
-        r = builder.src_suffixes(env)
+        r = bld.src_suffixes(env)
         assert r == ['.foo', '.bar'], r
 
-        builder.set_src_suffix(['.bar', '.foo'])
-        r = builder.get_src_suffix(env)
+        bld = SCons.Builder.Builder()
+        env = Environment(BUILDERS={'Bld':bld})
+
+        bld.set_src_suffix(['.bar', '.foo'])
+        r = bld.get_src_suffix(env)
         assert r == '.bar', r
-        r = builder.src_suffixes(env)
+        r = sorted(bld.src_suffixes(env))
         assert r == ['.bar', '.foo'], r
 
         # adjust_suffix normalizes the suffix, adding a `.' if needed
@@ -1144,20 +1099,20 @@ class BuilderTestCase(unittest.TestCase):
         assert r == 'A_', r
         r = builder.get_suffix(env)
         assert r == '.B', r
-        r = builder.get_prefix(env, ['X.C'])
+        r = builder.get_prefix(env, [MyNode('X.C')])
         assert r == 'E_', r
-        r = builder.get_suffix(env, ['X.C'])
+        r = builder.get_suffix(env, [MyNode('X.C')])
         assert r == '.D', r
 
         builder = SCons.Builder.Builder(prefix='A_', suffix={}, action={})
-
         env = Environment(BUILDERS={'Bld':builder})
+
         r = builder.get_name(env)
         assert r == 'Bld', r
         r = builder.get_prefix(env)
         assert r == 'A_', r
         r = builder.get_suffix(env)
-        assert r == None, r
+        assert r is None, r
         r = builder.get_src_suffix(env)
         assert r == '', r
         r = builder.src_suffixes(env)
@@ -1167,20 +1122,26 @@ class BuilderTestCase(unittest.TestCase):
         # whose keys are the source suffix.  The add_action()
         # specifies a new source suffix/action binding.
 
+        builder = SCons.Builder.Builder(prefix='A_', suffix={}, action={})
+        env = Environment(BUILDERS={'Bld':builder})
         builder.add_action('.src_sfx1', 'FOO')
+
         r = builder.get_name(env)
         assert r == 'Bld', r
         r = builder.get_prefix(env)
         assert r == 'A_', r
         r = builder.get_suffix(env)
-        assert r == None, r
-        r = builder.get_suffix(env, ['X.src_sfx1'])
-        assert r == None, r
+        assert r is None, r
+        r = builder.get_suffix(env, [MyNode('X.src_sfx1')])
+        assert r is None, r
         r = builder.get_src_suffix(env)
         assert r == '.src_sfx1', r
         r = builder.src_suffixes(env)
         assert r == ['.src_sfx1'], r
 
+        builder = SCons.Builder.Builder(prefix='A_', suffix={}, action={})
+        env = Environment(BUILDERS={'Bld':builder})
+        builder.add_action('.src_sfx1', 'FOO')
         builder.add_action('.src_sfx2', 'BAR')
 
         r = builder.get_name(env)
@@ -1188,10 +1149,10 @@ class BuilderTestCase(unittest.TestCase):
         r = builder.get_prefix(env)
         assert r == 'A_', r
         r = builder.get_suffix(env)
-        assert r ==  None, r
+        assert r is None, r
         r = builder.get_src_suffix(env)
         assert r == '.src_sfx1', r
-        r = builder.src_suffixes(env)
+        r = sorted(builder.src_suffixes(env))
         assert r == ['.src_sfx1', '.src_sfx2'], r
 
 
@@ -1237,14 +1198,14 @@ class BuilderTestCase(unittest.TestCase):
 
         tgt = builder(env, target='foo3', source='bar', foo=1)
         assert len(tgt) == 2, len(tgt)
-        assert 'foo3' in map(str, tgt), map(str, tgt)
-        assert 'bar1' in map(str, tgt), map(str, tgt)
+        assert 'foo3' in list(map(str, tgt)), list(map(str, tgt))
+        assert 'bar1' in list(map(str, tgt)), list(map(str, tgt))
 
         tgt = builder(env, target='foo4', source='bar', bar=1)[0]
         assert str(tgt) == 'foo4', str(tgt)
         assert len(tgt.sources) == 2, len(tgt.sources)
-        assert 'baz' in map(str, tgt.sources), map(str, tgt.sources)
-        assert 'bar' in map(str, tgt.sources), map(str, tgt.sources)
+        assert 'baz' in list(map(str, tgt.sources)), list(map(str, tgt.sources))
+        assert 'bar' in list(map(str, tgt.sources)), list(map(str, tgt.sources))
 
         env2=Environment(FOO=emit)
         builder2=SCons.Builder.Builder(action='foo',
@@ -1252,112 +1213,142 @@ class BuilderTestCase(unittest.TestCase):
                                        target_factory=MyNode,
                                        source_factory=MyNode)
 
+        builder2a=SCons.Builder.Builder(action='foo',
+                                        emitter="$FOO",
+                                        target_factory=MyNode,
+                                        source_factory=MyNode)
+
+        assert builder2 == builder2a, repr(builder2.__dict__) + "\n" + repr(builder2a.__dict__)
+
         tgt = builder2(env2, target='foo5', source='bar')[0]
         assert str(tgt) == 'foo5', str(tgt)
         assert str(tgt.sources[0]) == 'bar', str(tgt.sources[0])
 
         tgt = builder2(env2, target='foo6', source='bar', foo=2)
         assert len(tgt) == 2, len(tgt)
-        assert 'foo6' in map(str, tgt), map(str, tgt)
-        assert 'bar2' in map(str, tgt), map(str, tgt)
+        assert 'foo6' in list(map(str, tgt)), list(map(str, tgt))
+        assert 'bar2' in list(map(str, tgt)), list(map(str, tgt))
 
         tgt = builder2(env2, target='foo7', source='bar', bar=1)[0]
         assert str(tgt) == 'foo7', str(tgt)
         assert len(tgt.sources) == 2, len(tgt.sources)
-        assert 'baz' in map(str, tgt.sources), map(str, tgt.sources)
-        assert 'bar' in map(str, tgt.sources), map(str, tgt.sources)
+        assert 'baz' in list(map(str, tgt.sources)), list(map(str, tgt.sources))
+        assert 'bar' in list(map(str, tgt.sources)), list(map(str, tgt.sources))
 
-        builder2a=SCons.Builder.Builder(action='foo',
-                                        emitter="$FOO",
-                                        target_factory=MyNode,
-                                        source_factory=MyNode)
-        assert builder2 == builder2a, repr(builder2.__dict__) + "\n" + repr(builder2a.__dict__)
+    def test_emitter_preserve_builder(self):
+        """Test an emitter not overwriting a newly-set builder"""
+        env = Environment()
 
-        # Test that, if an emitter sets a builder on the passed-in
-        # targets and passes back new targets, the new builder doesn't
-        # get overwritten.
         new_builder = SCons.Builder.Builder(action='new')
         node = MyNode('foo8')
         new_node = MyNode('foo8.new')
-        def emit3(target, source, env, nb=new_builder, nn=new_node):
+
+        def emit(target, source, env, nb=new_builder, nn=new_node):
             for t in target:
                 t.builder = nb
             return [nn], source
             
-        builder3=SCons.Builder.Builder(action='foo',
-                                       emitter=emit3,
-                                       target_factory=MyNode,
-                                       source_factory=MyNode)
-        tgt = builder3(env, target=node, source='bar')[0]
+        builder=SCons.Builder.Builder(action='foo',
+                                      emitter=emit,
+                                      target_factory=MyNode,
+                                      source_factory=MyNode)
+        tgt = builder(env, target=node, source='bar')[0]
         assert tgt is new_node, tgt
-        assert tgt.builder is builder3, tgt.builder
+        assert tgt.builder is builder, tgt.builder
         assert node.builder is new_builder, node.builder
 
-        # Test use of a dictionary mapping file suffixes to
-        # emitter functions
+    def test_emitter_suffix_map(self):
+        """Test mapping file suffixes to emitter functions"""
+        env = Environment()
+
         def emit4a(target, source, env):
-            source = map(str, source)
-            target = map(lambda x: 'emit4a-' + x[:-3], source)
+            source = list(map(str, source))
+            target = ['emit4a-' + x[:-3] for x in source]
             return (target, source)
         def emit4b(target, source, env):
-            source = map(str, source)
-            target = map(lambda x: 'emit4b-' + x[:-3], source)
+            source = list(map(str, source))
+            target = ['emit4b-' + x[:-3] for x in source]
             return (target, source)
-        builder4 = SCons.Builder.Builder(action='foo',
-                                         emitter={'.4a':emit4a,
-                                                  '.4b':emit4b},
-                                         target_factory=MyNode,
-                                         source_factory=MyNode)
-        tgt = builder4(env, None, source='aaa.4a')[0]
+
+        builder = SCons.Builder.Builder(action='foo',
+                                        emitter={'.4a':emit4a,
+                                                 '.4b':emit4b},
+                                        target_factory=MyNode,
+                                        source_factory=MyNode)
+        tgt = builder(env, None, source='aaa.4a')[0]
         assert str(tgt) == 'emit4a-aaa', str(tgt)
-        tgt = builder4(env, None, source='bbb.4b')[0]
+        tgt = builder(env, None, source='bbb.4b')[0]
         assert str(tgt) == 'emit4b-bbb', str(tgt)
-        tgt = builder4(env, None, source='ccc.4c')[0]
+        tgt = builder(env, None, source='ccc.4c')[0]
         assert str(tgt) == 'ccc', str(tgt)
 
         def emit4c(target, source, env):
-            source = map(str, source)
-            target = map(lambda x: 'emit4c-' + x[:-3], source)
+            source = list(map(str, source))
+            target = ['emit4c-' + x[:-3] for x in source]
             return (target, source)
-        builder4.add_emitter('.4c', emit4c)
-        tgt = builder4(env, None, source='ccc.4c')[0]
+
+        builder.add_emitter('.4c', emit4c)
+        tgt = builder(env, None, source='ccc.4c')[0]
         assert str(tgt) == 'emit4c-ccc', str(tgt)
 
-        # Test a list of emitter functions.
-        def emit5a(target, source, env):
-            source = map(str, source)
-            target = target + map(lambda x: 'emit5a-' + x[:-2], source)
+    def test_emitter_function_list(self):
+        """Test lists of emitter functions"""
+        env = Environment()
+
+        def emit1a(target, source, env):
+            source = list(map(str, source))
+            target = target + ['emit1a-' + x[:-2] for x in source]
             return (target, source)
-        def emit5b(target, source, env):
-            source = map(str, source)
-            target = target + map(lambda x: 'emit5b-' + x[:-2], source)
+        def emit1b(target, source, env):
+            source = list(map(str, source))
+            target = target + ['emit1b-' + x[:-2] for x in source]
             return (target, source)
-        builder5 = SCons.Builder.Builder(action='foo',
-                                         emitter=[emit5a, emit5b],
+        builder1 = SCons.Builder.Builder(action='foo',
+                                         emitter=[emit1a, emit1b],
                                          node_factory=MyNode)
 
-        tgts = builder5(env, target='target-5', source='aaa.5')
-        tgts = map(str, tgts)
-        assert tgts == ['target-5', 'emit5a-aaa', 'emit5b-aaa'], tgts
+        tgts = builder1(env, target='target-1', source='aaa.1')
+        tgts = list(map(str, tgts))
+        assert tgts == ['target-1', 'emit1a-aaa', 'emit1b-aaa'], tgts
 
         # Test a list of emitter functions through the environment.
-        def emit6a(target, source, env):
-            source = map(str, source)
-            target = target + map(lambda x: 'emit6a-' + x[:-2], source)
+        def emit2a(target, source, env):
+            source = list(map(str, source))
+            target = target + ['emit2a-' + x[:-2] for x in source]
             return (target, source)
-        def emit6b(target, source, env):
-            source = map(str, source)
-            target = target + map(lambda x: 'emit6b-' + x[:-2], source)
+        def emit2b(target, source, env):
+            source = list(map(str, source))
+            target = target + ['emit2b-' + x[:-2] for x in source]
             return (target, source)
-        builder6 = SCons.Builder.Builder(action='foo',
+        builder2 = SCons.Builder.Builder(action='foo',
                                          emitter='$EMITTERLIST',
                                          node_factory=MyNode)
                                          
-        env = Environment(EMITTERLIST = [emit6a, emit6b])
+        env = Environment(EMITTERLIST = [emit2a, emit2b])
+
+        tgts = builder2(env, target='target-2', source='aaa.2')
+        tgts = list(map(str, tgts))
+        assert tgts == ['target-2', 'emit2a-aaa', 'emit2b-aaa'], tgts
+
+    def test_emitter_TARGET_SOURCE(self):
+        """Test use of $TARGET and $SOURCE in emitter results"""
+
+        env = SCons.Environment.Environment()
+
+        def emit(target, source, env):
+            return (target + ['${SOURCE}.s1', '${TARGET}.t1'],
+                    source + ['${TARGET}.t2', '${SOURCE}.s2'])
 
-        tgts = builder6(env, target='target-6', source='aaa.6')
-        tgts = map(str, tgts)
-        assert tgts == ['target-6', 'emit6a-aaa', 'emit6b-aaa'], tgts
+        builder = SCons.Builder.Builder(action='foo',
+                                        emitter = emit,
+                                        node_factory = MyNode)
+
+        targets = builder(env, target = 'TTT', source ='SSS')
+        sources = targets[0].sources
+        targets = list(map(str, targets))
+        sources = list(map(str, sources))
+        assert targets == ['TTT', 'SSS.s1', 'TTT.t1'], targets
+        assert sources == ['SSS', 'TTT.t2', 'SSS.s2'], targets
 
     def test_no_target(self):
         """Test deducing the target from the source."""
@@ -1367,53 +1358,53 @@ class BuilderTestCase(unittest.TestCase):
 
         tgt = b(env, None, 'aaa')[0]
         assert str(tgt) == 'aaa.o', str(tgt)
-        assert len(tgt.sources) == 1, map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'aaa', map(str, tgt.sources)
+        assert len(tgt.sources) == 1, list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'aaa', list(map(str, tgt.sources))
 
         tgt = b(env, None, 'bbb.c')[0]
         assert str(tgt) == 'bbb.o', str(tgt)
-        assert len(tgt.sources) == 1, map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'bbb.c', map(str, tgt.sources)
+        assert len(tgt.sources) == 1, list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'bbb.c', list(map(str, tgt.sources))
 
         tgt = b(env, None, 'ccc.x.c')[0]
         assert str(tgt) == 'ccc.x.o', str(tgt)
-        assert len(tgt.sources) == 1, map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'ccc.x.c', map(str, tgt.sources)
+        assert len(tgt.sources) == 1, list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'ccc.x.c', list(map(str, tgt.sources))
 
         tgt = b(env, None, ['d0.c', 'd1.c'])[0]
         assert str(tgt) == 'd0.o', str(tgt)
-        assert len(tgt.sources) == 2,  map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'd0.c', map(str, tgt.sources)
-        assert str(tgt.sources[1]) == 'd1.c', map(str, tgt.sources)
+        assert len(tgt.sources) == 2,  list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'd0.c', list(map(str, tgt.sources))
+        assert str(tgt.sources[1]) == 'd1.c', list(map(str, tgt.sources))
 
         tgt = b(env, target = None, source='eee')[0]
         assert str(tgt) == 'eee.o', str(tgt)
-        assert len(tgt.sources) == 1, map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'eee', map(str, tgt.sources)
+        assert len(tgt.sources) == 1, list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'eee', list(map(str, tgt.sources))
 
         tgt = b(env, target = None, source='fff.c')[0]
         assert str(tgt) == 'fff.o', str(tgt)
-        assert len(tgt.sources) == 1, map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'fff.c', map(str, tgt.sources)
+        assert len(tgt.sources) == 1, list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'fff.c', list(map(str, tgt.sources))
 
         tgt = b(env, target = None, source='ggg.x.c')[0]
         assert str(tgt) == 'ggg.x.o', str(tgt)
-        assert len(tgt.sources) == 1, map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'ggg.x.c', map(str, tgt.sources)
+        assert len(tgt.sources) == 1, list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'ggg.x.c', list(map(str, tgt.sources))
 
         tgt = b(env, target = None, source=['h0.c', 'h1.c'])[0]
         assert str(tgt) == 'h0.o', str(tgt)
-        assert len(tgt.sources) == 2,  map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'h0.c', map(str, tgt.sources)
-        assert str(tgt.sources[1]) == 'h1.c', map(str, tgt.sources)
+        assert len(tgt.sources) == 2,  list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'h0.c', list(map(str, tgt.sources))
+        assert str(tgt.sources[1]) == 'h1.c', list(map(str, tgt.sources))
 
         w = b(env, target='i0.w', source=['i0.x'])[0]
         y = b(env, target='i1.y', source=['i1.z'])[0]
         tgt = b(env, None, source=[w, y])[0]
         assert str(tgt) == 'i0.o', str(tgt)
-        assert len(tgt.sources) == 2, map(str, tgt.sources)
-        assert str(tgt.sources[0]) == 'i0.w', map(str, tgt.sources)
-        assert str(tgt.sources[1]) == 'i1.y', map(str, tgt.sources)
+        assert len(tgt.sources) == 2, list(map(str, tgt.sources))
+        assert str(tgt.sources[0]) == 'i0.w', list(map(str, tgt.sources))
+        assert str(tgt.sources[1]) == 'i1.y', list(map(str, tgt.sources))
 
     def test_get_name(self):
         """Test getting name of builder.
@@ -1423,9 +1414,8 @@ class BuilderTestCase(unittest.TestCase):
 
         b1 = SCons.Builder.Builder(action='foo', suffix='.o')
         b2 = SCons.Builder.Builder(action='foo', suffix='.c')
-        b3 = SCons.Builder.MultiStepBuilder(action='bar',
-                                            src_suffix = '.foo',
-                                            src_builder = b1)
+        b3 = SCons.Builder.Builder(action='bar', src_suffix = '.foo',
+                                                 src_builder = b1)
         b4 = SCons.Builder.Builder(action={})
         b5 = SCons.Builder.Builder(action='foo', name='builder5')
         b6 = SCons.Builder.Builder(action='foo')
@@ -1440,50 +1430,224 @@ class BuilderTestCase(unittest.TestCase):
                                      'B2': b2,
                                      'B3': b3,
                                      'B4': b4})
-        assert b1.get_name(env) == 'bldr1', b1.get_name(env)
-        assert b2.get_name(env) == 'bldr2', b2.get_name(env)
-        assert b3.get_name(env) == 'bldr3', b3.get_name(env)
-        assert b4.get_name(env) == 'bldr4', b4.get_name(env)
-        assert b5.get_name(env) == 'builder5', b5.get_name(env)
         # With no name, get_name will return the class.  Allow
         # for caching...
-        assert b6.get_name(env) in [
+        b6_names = [
             'SCons.Builder.BuilderBase',
             "<class 'SCons.Builder.BuilderBase'>",
             'SCons.Memoize.BuilderBase',
             "<class 'SCons.Memoize.BuilderBase'>",
-            ], b6.get_name(env)
+        ]
+
+        assert b1.get_name(env) == 'bldr1', b1.get_name(env)
+        assert b2.get_name(env) == 'bldr2', b2.get_name(env)
+        assert b3.get_name(env) == 'bldr3', b3.get_name(env)
+        assert b4.get_name(env) == 'bldr4', b4.get_name(env)
+        assert b5.get_name(env) == 'builder5', b5.get_name(env)
+        assert b6.get_name(env) in b6_names, b6.get_name(env)
+
         assert b1.get_name(env2) == 'B1', b1.get_name(env2)
         assert b2.get_name(env2) == 'B2', b2.get_name(env2)
         assert b3.get_name(env2) == 'B3', b3.get_name(env2)
         assert b4.get_name(env2) == 'B4', b4.get_name(env2)
         assert b5.get_name(env2) == 'builder5', b5.get_name(env2)
-        assert b6.get_name(env2) in [
-            'SCons.Builder.BuilderBase',
-            "<class 'SCons.Builder.BuilderBase'>",
-            'SCons.Memoize.BuilderBase',
-            "<class 'SCons.Memoize.BuilderBase'>",
-            ], b6.get_name(env2)
+        assert b6.get_name(env2) in b6_names, b6.get_name(env2)
 
-        for B in b3.get_src_builders(env):
-            assert B.get_name(env) == 'bldr1'
-        for B in b3.get_src_builders(env2):
-            assert B.get_name(env2) == 'B1'
+        assert b5.get_name(None) == 'builder5', b5.get_name(None)
+        assert b6.get_name(None) in b6_names, b6.get_name(None)
 
-        tgts = b1(env, target = [outfile, outfile2], source='moo')
-        for t in tgts:
-            assert t.builder.get_name(env) == 'ListBuilder(bldr1)'
-            # The following are not symbolically correct, because the
-            # ListBuilder was only created on behalf of env, so it
-            # would probably be OK if better correctness
-            # env-to-builder mappings caused this to fail in the
-            # future.
-            assert t.builder.get_name(env2) == 'ListBuilder(B1)'
+        # This test worked before adding batch builders, but we must now
+        # be able to disambiguate a CompositeAction into a more specific
+        # action based on file suffix at call time.  Leave this commented
+        # out (for now) in case this reflects a real-world use case that
+        # we must accomodate and we want to resurrect this test.
+        #tgt = b4(env, target = 'moo', source='cow')
+        #assert tgt[0].builder.get_name(env) == 'bldr4'
+
+class CompositeBuilderTestCase(unittest.TestCase):
 
-        tgt = b4(env, target = 'moo', source='cow')
-        assert tgt[0].builder.get_name(env) == 'bldr4'
+    def setUp(self):
+        def func_action(target, source, env):
+            return 0
+
+        builder = SCons.Builder.Builder(action={ '.foo' : func_action,
+                                                 '.bar' : func_action})
+
+        self.func_action = func_action
+        self.builder = builder
+
+    def test___init__(self):
+        """Test CompositeBuilder creation"""
+        env = Environment()
+        builder = SCons.Builder.Builder(action={})
+
+        tgt = builder(env, source=[])
+        assert tgt == [], tgt
+        
+        assert isinstance(builder, SCons.Builder.CompositeBuilder)
+        assert isinstance(builder.action, SCons.Action.CommandGeneratorAction)
+
+    def test_target_action(self):
+        """Test CompositeBuilder setting of target builder actions"""
+        env = Environment()
+        builder = self.builder
+
+        tgt = builder(env, target='test1', source='test1.foo')[0]
+        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
+        assert tgt.builder.action is builder.action
+
+        tgt = builder(env, target='test2', source='test1.bar')[0]
+        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
+        assert tgt.builder.action is builder.action
+
+    def test_multiple_suffix_error(self):
+        """Test the CompositeBuilder multiple-source-suffix error"""
+        env = Environment()
+        builder = self.builder
+
+        flag = 0
+        try:
+            builder(env, target='test3', source=['test2.bar', 'test1.foo'])[0]
+        except SCons.Errors.UserError, e:
+            flag = 1
+        assert flag, "UserError should be thrown when we call a builder with files of different suffixes."
+        expect = "While building `['test3']' from `test1.foo': Cannot build multiple sources with different extensions: .bar, .foo"
+        assert str(e) == expect, e
+
+    def test_source_ext_match(self):
+        """Test the CompositeBuilder source_ext_match argument"""
+        env = Environment()
+        func_action = self.func_action
+        builder = SCons.Builder.Builder(action={ '.foo' : func_action,
+                                                 '.bar' : func_action},
+                                        source_ext_match = None)
+
+        tgt = builder(env, target='test3', source=['test2.bar', 'test1.foo'])[0]
+        tgt.build()
+
+    def test_suffix_variable(self):
+        """Test CompositeBuilder defining action suffixes through a variable"""
+        env = Environment(BAR_SUFFIX = '.BAR2', FOO_SUFFIX = '.FOO2')
+        func_action = self.func_action
+        builder = SCons.Builder.Builder(action={ '.foo' : func_action,
+                                                 '.bar' : func_action,
+                                                 '$BAR_SUFFIX' : func_action,
+                                                 '$FOO_SUFFIX' : func_action })
+
+        tgt = builder(env, target='test4', source=['test4.BAR2'])[0]
+        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
+        try:
+            tgt.build()
+            flag = 1
+        except SCons.Errors.UserError, e:
+            print e
+            flag = 0
+        assert flag, "It should be possible to define actions in composite builders using variables."
+        env['FOO_SUFFIX'] = '.BAR2'
+        builder.add_action('$NEW_SUFFIX', func_action)
+        flag = 0
+        try:
+            builder(env, target='test5', source=['test5.BAR2'])[0]
+        except SCons.Errors.UserError:
+            flag = 1
+        assert flag, "UserError should be thrown when we call a builder with ambigous suffixes."
+
+    def test_src_builder(self):
+        """Test CompositeBuilder's use of a src_builder"""
+        env = Environment()
+
+        foo_bld = SCons.Builder.Builder(action = 'a-foo',
+                                        src_suffix = '.ina',
+                                        suffix = '.foo')
+        assert isinstance(foo_bld, SCons.Builder.BuilderBase)
+        builder = SCons.Builder.Builder(action = { '.foo' : 'foo',
+                                                   '.bar' : 'bar' },
+                                        src_builder = foo_bld)
+        assert isinstance(builder, SCons.Builder.CompositeBuilder)
+        assert isinstance(builder.action, SCons.Action.CommandGeneratorAction)
+
+        tgt = builder(env, target='t1', source='t1a.ina t1b.ina')[0]
+        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
+
+        tgt = builder(env, target='t2', source='t2a.foo t2b.ina')[0]
+        assert isinstance(tgt.builder, SCons.Builder.BuilderBase), tgt.builder.__dict__
+
+        bar_bld = SCons.Builder.Builder(action = 'a-bar',
+                                        src_suffix = '.inb',
+                                        suffix = '.bar')
+        assert isinstance(bar_bld, SCons.Builder.BuilderBase)
+        builder = SCons.Builder.Builder(action = { '.foo' : 'foo'},
+                                        src_builder = [foo_bld, bar_bld])
+        assert isinstance(builder, SCons.Builder.CompositeBuilder)
+        assert isinstance(builder.action, SCons.Action.CommandGeneratorAction)
+
+        builder.add_action('.bar', 'bar')
+
+        tgt = builder(env, target='t3-foo', source='t3a.foo t3b.ina')[0]
+        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
+
+        tgt = builder(env, target='t3-bar', source='t3a.bar t3b.inb')[0]
+        assert isinstance(tgt.builder, SCons.Builder.BuilderBase)
+
+        flag = 0
+        try:
+            builder(env, target='t5', source=['test5a.foo', 'test5b.inb'])[0]
+        except SCons.Errors.UserError, e:
+            flag = 1
+        assert flag, "UserError should be thrown when we call a builder with files of different suffixes."
+        expect = "While building `['t5']' from `test5b.bar': Cannot build multiple sources with different extensions: .foo, .bar"
+        assert str(e) == expect, e
+
+        flag = 0
+        try:
+            builder(env, target='t6', source=['test6a.bar', 'test6b.ina'])[0]
+        except SCons.Errors.UserError, e:
+            flag = 1
+        assert flag, "UserError should be thrown when we call a builder with files of different suffixes."
+        expect = "While building `['t6']' from `test6b.foo': Cannot build multiple sources with different extensions: .bar, .foo"
+        assert str(e) == expect, e
+
+        flag = 0
+        try:
+            builder(env, target='t4', source=['test4a.ina', 'test4b.inb'])[0]
+        except SCons.Errors.UserError, e:
+            flag = 1
+        assert flag, "UserError should be thrown when we call a builder with files of different suffixes."
+        expect = "While building `['t4']' from `test4b.bar': Cannot build multiple sources with different extensions: .foo, .bar"
+        assert str(e) == expect, e
+
+        flag = 0
+        try:
+            builder(env, target='t7', source=[env.fs.File('test7')])[0]
+        except SCons.Errors.UserError, e:
+            flag = 1
+        assert flag, "UserError should be thrown when we call a builder with files of different suffixes."
+        expect = "While building `['t7']': Cannot deduce file extension from source files: ['test7']"
+        assert str(e) == expect, e
+
+        flag = 0
+        try:
+            builder(env, target='t8', source=['test8.unknown'])[0]
+        except SCons.Errors.UserError, e:
+            flag = 1
+        assert flag, "UserError should be thrown when we call a builder target with an unknown suffix."
+        expect = "While building `['t8']' from `['test8.unknown']': Don't know how to build from a source file with suffix `.unknown'.  Expected a suffix in this list: ['.foo', '.bar']."
+        assert str(e) == expect, e
 
 if __name__ == "__main__":
-    suite = unittest.makeSuite(BuilderTestCase, 'test_')
+    suite = unittest.TestSuite()
+    tclasses = [
+        BuilderTestCase,
+        CompositeBuilderTestCase
+    ]
+    for tclass in tclasses:
+        names = unittest.getTestCaseNames(tclass, 'test_')
+        suite.addTests(list(map(tclass, names)))
     if not unittest.TextTestRunner().run(suite).wasSuccessful():
         sys.exit(1)
+
+# Local Variables:
+# tab-width:4
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=4 shiftwidth=4: