Handle shared memory symbols better in the binarysize tool.

tools/binary_size/explain_binary_size_delta_unittest.py

Index: tools/binary_size/explain_binary_size_delta_unittest.py
diff --git a/tools/binary_size/explain_binary_size_delta_unittest.py b/tools/binary_size/explain_binary_size_delta_unittest.py
index 87ecb3680d62ea5c497007b57cafd51b77150fce..d818d83f24c40fb59c537a124308aaaf0334e8f7 100755
--- a/tools/binary_size/explain_binary_size_delta_unittest.py
+++ b/tools/binary_size/explain_binary_size_delta_unittest.py
@@ -15,114 +15,122 @@ import explain_binary_size_delta
 class ExplainBinarySizeDeltaTest(unittest.TestCase):
 
   def testCompare(self):
-    # List entries have form: symbol_name, symbol_type, symbol_size, file_path
+    # List entries have form:
+    # symbol_name, symbol_type, symbol_size, file_path, memory_address
     symbol_list1 = (
       # File with one symbol, left as-is.
-      ( 'unchanged', 't', 1000, '/file_unchanged' ),
+      ( 'unchanged', 't', 1000, '/file_unchanged', 0x1 ),
       # File with one symbol, changed.
-      ( 'changed', 't', 1000, '/file_all_changed' ),
+      ( 'changed', 't', 1000, '/file_all_changed', 0x2 ),
       # File with one symbol, deleted.
-      ( 'removed', 't', 1000, '/file_all_deleted' ),
+      ( 'removed', 't', 1000, '/file_all_deleted', 0x3 ),
       # File with two symbols, one unchanged, one changed, same bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_changed' ),
-      ( 'changed', 't', 1000, '/file_pair_unchanged_changed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_changed', 0x4 ),
+      ( 'changed', 't', 1000, '/file_pair_unchanged_changed', 0x5 ),
       # File with two symbols, one unchanged, one deleted, same bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_removed' ),
-      ( 'removed', 't', 1000, '/file_pair_unchanged_removed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_removed', 0x6 ),
+      ( 'removed', 't', 1000, '/file_pair_unchanged_removed', 0x7 ),
       # File with two symbols, one unchanged, one added, same bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_added' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_added', 0x8 ),
       # File with two symbols, one unchanged, one changed, different bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_changed' ),
-      ( 'changed', '@', 1000, '/file_pair_unchanged_diffbuck_changed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_changed', 0x9 ),
+      ( 'changed', '@', 1000, '/file_pair_unchanged_diffbuck_changed', 0xa ),
       # File with two symbols, one unchanged, one deleted, different bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_removed' ),
-      ( 'removed', '@', 1000, '/file_pair_unchanged_diffbuck_removed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_removed', 0xb ),
+      ( 'removed', '@', 1000, '/file_pair_unchanged_diffbuck_removed', 0xc ),
       # File with two symbols, one unchanged, one added, different bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_added' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_added', 0xd ),
       # File with four symbols, one added, one removed,
       # one changed, one unchanged
-      ( 'size_changed', 't', 1000, '/file_tetra' ),
-      ( 'removed', 't', 1000, '/file_tetra' ),
-      ( 'unchanged', 't', 1000, '/file_tetra' ),
+      ( 'size_changed', 't', 1000, '/file_tetra', 0xe ),
+      ( 'removed', 't', 1000, '/file_tetra', 0xf ),
+      ( 'unchanged', 't', 1000, '/file_tetra', 0x10 ),
     )
 
     symbol_list2 = (
       # File with one symbol, left as-is.
-      ( 'unchanged', 't', 1000, '/file_unchanged' ),
+      ( 'unchanged', 't', 1000, '/file_unchanged', 0x1 ),
       # File with one symbol, changed.
-      ( 'changed', 't', 2000, '/file_all_changed' ),
+      ( 'changed', 't', 2000, '/file_all_changed', 0x2 ),
       # File with two symbols, one unchanged, one changed, same bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_changed' ),
-      ( 'changed', 't', 2000, '/file_pair_unchanged_changed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_changed', 0x3 ),
+      ( 'changed', 't', 2000, '/file_pair_unchanged_changed', 0x4 ),
       # File with two symbols, one unchanged, one deleted, same bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_removed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_removed', 0x5 ),
       # File with two symbols, one unchanged, one added, same bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_added' ),
-      ( 'added', 't', 1000, '/file_pair_unchanged_added' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_added', 0x6 ),
+      ( 'added', 't', 1000, '/file_pair_unchanged_added', 0x7 ),
       # File with two symbols, one unchanged, one changed, different bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_changed' ),
-      ( 'changed', '@', 2000, '/file_pair_unchanged_diffbuck_changed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_changed', 0x8 ),
+      ( 'changed', '@', 2000, '/file_pair_unchanged_diffbuck_changed', 0x9 ),
       # File with two symbols, one unchanged, one deleted, different bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_removed' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_removed', 0xa ),
       # File with two symbols, one unchanged, one added, different bucket
-      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_added' ),
-      ( 'added', '@', 1000, '/file_pair_unchanged_diffbuck_added' ),
+      ( 'unchanged', 't', 1000, '/file_pair_unchanged_diffbuck_added', 0xb ),
+      ( 'added', '@', 1000, '/file_pair_unchanged_diffbuck_added', 0xc ),
       # File with four symbols, one added, one removed,
       # one changed, one unchanged
-      ( 'size_changed', 't', 2000, '/file_tetra' ),
-      ( 'unchanged', 't', 1000, '/file_tetra' ),
-      ( 'added', 't', 1000, '/file_tetra' ),
+      ( 'size_changed', 't', 2000, '/file_tetra', 0xd ),
+      ( 'unchanged', 't', 1000, '/file_tetra', 0xe ),
+      ( 'added', 't', 1000, '/file_tetra', 0xf ),
       # New file with one symbol added
-      ( 'added', 't', 1000, '/file_new' ),
+      ( 'added', 't', 1000, '/file_new', 0x10 ),
     )
 
     # Here we go
     (added, removed, changed, unchanged) = \
         explain_binary_size_delta.Compare(symbol_list1, symbol_list2)
 
+    def delta(file_path, symbol_type, symbol_name, old_size, new_size):
+      delta_info = explain_binary_size_delta.DeltaInfo(
+        file_path, symbol_type, symbol_name, False)
+      delta_info.old_size = old_size
+      delta_info.new_size = new_size
+      return delta_info
+
     # File with one symbol, left as-is.
-    assert ('/file_unchanged', 't', 'unchanged', 1000, 1000) in unchanged
+    assert delta('/file_unchanged', 't', 'unchanged', 1000, 1000) in unchanged
     # File with one symbol, changed.
-    assert ('/file_all_changed', 't', 'changed', 1000, 2000) in changed
+    assert delta('/file_all_changed', 't', 'changed', 1000, 2000) in changed
     # File with one symbol, deleted.
-    assert ('/file_all_deleted', 't', 'removed', 1000, None) in removed
+    assert delta('/file_all_deleted', 't', 'removed', 1000, None) in removed
     # New file with one symbol added
-    assert ('/file_new', 't', 'added', None, 1000) in added
+    assert delta('/file_new', 't', 'added', None, 1000) in added
     # File with two symbols, one unchanged, one changed, same bucket
-    assert ('/file_pair_unchanged_changed',
+    assert delta('/file_pair_unchanged_changed',
             't', 'unchanged', 1000, 1000) in unchanged
-    assert ('/file_pair_unchanged_changed',
+    assert delta('/file_pair_unchanged_changed',
             't', 'changed', 1000, 2000) in changed
     # File with two symbols, one unchanged, one removed, same bucket
-    assert ('/file_pair_unchanged_removed',
+    assert delta('/file_pair_unchanged_removed',
             't', 'unchanged', 1000, 1000) in unchanged
-    assert ('/file_pair_unchanged_removed',
+    assert delta('/file_pair_unchanged_removed',
             't', 'removed', 1000, None) in removed
     # File with two symbols, one unchanged, one added, same bucket
-    assert ('/file_pair_unchanged_added',
+    assert delta('/file_pair_unchanged_added',
             't', 'unchanged', 1000, 1000) in unchanged
-    assert ('/file_pair_unchanged_added',
+    assert delta('/file_pair_unchanged_added',
             't', 'added', None, 1000) in added
     # File with two symbols, one unchanged, one changed, different bucket
-    assert ('/file_pair_unchanged_diffbuck_changed',
+    assert delta('/file_pair_unchanged_diffbuck_changed',
             't', 'unchanged', 1000, 1000) in unchanged
-    assert ('/file_pair_unchanged_diffbuck_changed',
+    assert delta('/file_pair_unchanged_diffbuck_changed',
             '@', 'changed', 1000, 2000) in changed
     # File with two symbols, one unchanged, one removed, different bucket
-    assert ('/file_pair_unchanged_diffbuck_removed',
+    assert delta('/file_pair_unchanged_diffbuck_removed',
             't', 'unchanged', 1000, 1000) in unchanged
-    assert ('/file_pair_unchanged_diffbuck_removed',
+    assert delta('/file_pair_unchanged_diffbuck_removed',
             '@', 'removed', 1000, None) in removed
     # File with two symbols, one unchanged, one added, different bucket
-    assert ('/file_pair_unchanged_diffbuck_added',
+    assert delta('/file_pair_unchanged_diffbuck_added',
             't', 'unchanged', 1000, 1000) in unchanged
-    assert ('/file_pair_unchanged_diffbuck_added',
+    assert delta('/file_pair_unchanged_diffbuck_added',
             '@', 'added', None, 1000) in added
     # File with four symbols, one added, one removed, one changed, one unchanged
-    assert ('/file_tetra', 't', 'size_changed', 1000, 2000) in changed
-    assert ('/file_tetra', 't', 'unchanged', 1000, 1000) in unchanged
-    assert ('/file_tetra', 't', 'added', None, 1000) in added
-    assert ('/file_tetra', 't', 'removed', 1000, None) in removed
+    assert delta('/file_tetra', 't', 'size_changed', 1000, 2000) in changed
+    assert delta('/file_tetra', 't', 'unchanged', 1000, 1000) in unchanged
+    assert delta('/file_tetra', 't', 'added', None, 1000) in added
+    assert delta('/file_tetra', 't', 'removed', 1000, None) in removed
 
     # Now check final stats.
     orig_stdout = sys.stdout
@@ -218,20 +226,20 @@ Per-source Analysis:
 
     self.maxDiff = None
     self.assertMultiLineEqual(expected_output, result)
-    print "explain_binary_size_delta_unittest: All tests passed"
 
 
   def testCompareStringEntries(self):
-    # List entries have form: symbol_name, symbol_type, symbol_size, file_path
+    # List entries have form:
+    # symbol_name, symbol_type, symbol_size, file_path, memory_address
     symbol_list1 = (
       # File with one string.
-      ( '.L.str107', 'r', 8, '/file_with_strs' ),
+      ( '.L.str107', 'r', 8, '/file_with_strs', 0x1 ),
     )
 
     symbol_list2 = (
       # Two files with one string each, same name.
-      ( '.L.str107', 'r', 8, '/file_with_strs' ),
-      ( '.L.str107', 'r', 7, '/other_file_with_strs' ),
+      ( '.L.str107', 'r', 8, '/file_with_strs', 0x1 ),
+      ( '.L.str107', 'r', 7, '/other_file_with_strs', 0x2 ),
     )
 
     # Here we go
@@ -272,29 +280,29 @@ Per-source Analysis:
 
     self.maxDiff = None
     self.assertMultiLineEqual(expected_output, result)
-    print "explain_binary_size_delta_unittest: All tests passed"
 
   def testCompareStringEntriesWithNoFile(self):
-    # List entries have form: symbol_name, symbol_type, symbol_size, file_path
+    # List entries have form:
+    # symbol_name, symbol_type, symbol_size, file_path, memory_address
     symbol_list1 = (
-      ( '.L.str104', 'r', 21, '??' ), # Will change size.
-      ( '.L.str105', 'r', 17, '??' ), # Same.
-      ( '.L.str106', 'r', 13, '??' ), # Will be removed.
-      ( '.L.str106', 'r', 3, '??' ), # Same.
-      ( '.L.str106', 'r', 3, '??' ), # Will be removed.
-      ( '.L.str107', 'r', 8, '??' ), # Will be removed (other sizes).
+      ( '.L.str104', 'r', 21, '??', 0x1 ), # Will change size.
+      ( '.L.str105', 'r', 17, '??', 0x2 ), # Same.
+      ( '.L.str106', 'r', 13, '??', 0x3 ), # Will be removed.
+      ( '.L.str106', 'r', 3, '??', 0x4 ), # Same.
+      ( '.L.str106', 'r', 3, '??', 0x5 ), # Will be removed.
+      ( '.L.str107', 'r', 8, '??', 0x6 ), # Will be removed (other sizes).
     )
 
     symbol_list2 = (
       # Two files with one string each, same name.
-      ( '.L.str104', 'r', 19, '??' ), # Changed.
-      ( '.L.str105', 'r', 11, '??' ), # New size for multi-symbol.
-      ( '.L.str105', 'r', 17, '??' ), # New of same size for multi-symbol.
-      ( '.L.str105', 'r', 17, '??' ), # Same.
-      ( '.L.str106', 'r', 3, '??' ), # Same.
-      ( '.L.str107', 'r', 5, '??' ), # New size for symbol.
-      ( '.L.str107', 'r', 7, '??' ), # New size for symbol.
-      ( '.L.str108', 'r', 8, '??' ), # New symbol.
+      ( '.L.str104', 'r', 19, '??', 0x1 ), # Changed.
+      ( '.L.str105', 'r', 11, '??', 0x2 ), # New size for multi-symbol.
+      ( '.L.str105', 'r', 17, '??', 0x3 ), # New of same size for multi-symbol.
+      ( '.L.str105', 'r', 17, '??', 0x4 ), # Same.
+      ( '.L.str106', 'r', 3, '??', 0x5 ), # Same.
+      ( '.L.str107', 'r', 5, '??', 0x6 ), # New size for symbol.
+      ( '.L.str107', 'r', 7, '??', 0x7 ), # New size for symbol.
+      ( '.L.str108', 'r', 8, '??', 0x8 ), # New symbol.
     )
 
     # Here we go
@@ -348,7 +356,266 @@ Per-source Analysis:
 
     self.maxDiff = None
     self.assertMultiLineEqual(expected_output, result)
-    print "explain_binary_size_delta_unittest: All tests passed"
+
+  def testCompareSharedSpace(self):
+    # List entries have form:
+    # symbol_name, symbol_type, symbol_size, file_path, memory_address
+    symbol_list1 = (
+      # File with two symbols, same address.
+      ( 'sym1', 'r', 8, '/file', 0x1 ),
+      ( 'sym2', 'r', 8, '/file', 0x1 ),
+    )
+
+    symbol_list2 = (
+      # File with two symbols, same address.
+      ( 'sym1', 'r', 4, '/file', 0x1 ),
+      ( 'sym2', 'r', 4, '/file', 0x1 ),
+    )
+
+    # Here we go
+    (added, removed, changed, unchanged) = \
+        explain_binary_size_delta.Compare(symbol_list1, symbol_list2)
+
+
+    # Now check final stats.
+    orig_stdout = sys.stdout
+    output_collector = cStringIO.StringIO()
+    sys.stdout = output_collector
+    try:
+      explain_binary_size_delta.CrunchStats(added, removed, changed,
+                                            unchanged, True, True)
+    finally:
+      sys.stdout = orig_stdout
+    result = output_collector.getvalue()
+
+    expected_output = """\
+Total change: -4 bytes
+======================
+  2 shrunk, for a net change of -4 bytes (8 bytes before, 4 bytes after) \
+across 1 sources
+  0 unchanged, totalling 0 bytes
+Source stats:
+  1 sources encountered.
+  0 completely new.
+  0 removed completely.
+  1 partially changed.
+  0 completely unchanged.
+Per-source Analysis:
+
+----------------------------------------
+ -4 - Source: /file - (gained 0, lost 4)
+----------------------------------------
+  Shrunk symbols:
+         -2: sym1 type=r, (was 4 bytes, now 2 bytes) (adjusted sizes because \
+of memory sharing)
+         -2: sym2 type=r, (was 4 bytes, now 2 bytes) (adjusted sizes because \
+of memory sharing)
+"""
+
+    self.maxDiff = None
+    self.assertMultiLineEqual(expected_output, result)
+
+
+  def testCompareSharedSpaceDuplicateSymbols(self):
+    # List entries have form:
+    # symbol_name, symbol_type, symbol_size, file_path, memory_address
+    symbol_list1 = (
+      # File with two symbols, same address.
+      ( 'sym1', 'r', 7, '/file', 0x2 ),
+      ( 'sym1', 'r', 8, '/file', 0x1 ),
+      ( 'sym2', 'r', 8, '/file', 0x1 ),
+    )
+
+    symbol_list2 = (
+      # File with two symbols, same address.
+      ( 'sym1', 'r', 7, '/file', 0x2 ),
+      ( 'sym1', 'r', 4, '/file', 0x1 ),
+      ( 'sym2', 'r', 4, '/file', 0x1 ),
+    )
+
+    # Here we go
+    (added, removed, changed, unchanged) = \
+        explain_binary_size_delta.Compare(symbol_list1, symbol_list2)
+
+
+    # Now check final stats.
+    orig_stdout = sys.stdout
+    output_collector = cStringIO.StringIO()
+    sys.stdout = output_collector
+    try:
+      explain_binary_size_delta.CrunchStats(added, removed, changed,
+                                            unchanged, True, True)
+    finally:
+      sys.stdout = orig_stdout
+    result = output_collector.getvalue()
+
+    expected_output = """\
+Total change: -4 bytes
+======================
+  1 added, totalling +2 bytes across 1 sources
+  1 removed, totalling -4 bytes across 1 sources
+  1 shrunk, for a net change of -2 bytes (4 bytes before, 2 bytes after) \
+across 1 sources
+  1 unchanged, totalling 7 bytes
+Source stats:
+  1 sources encountered.
+  0 completely new.
+  0 removed completely.
+  1 partially changed.
+  0 completely unchanged.
+Per-source Analysis:
+
+----------------------------------------
+ -4 - Source: /file - (gained 2, lost 6)
+----------------------------------------
+  New symbols:
+         +2: sym1 type=r, size=2 bytes (adjusted sizes because of memory \
+sharing)
+  Removed symbols:
+         -4: sym1 type=r, size=4 bytes (adjusted sizes because of memory \
+sharing)
+  Shrunk symbols:
+         -2: sym2 type=r, (was 4 bytes, now 2 bytes) (adjusted sizes because \
+of memory sharing)
+"""
+
+    self.maxDiff = None
+    self.assertMultiLineEqual(expected_output, result)
+
+  def testCompareSharedSpaceBecomingUnshared(self):
+    # List entries have form:
+    # symbol_name, symbol_type, symbol_size, file_path, memory_address
+    symbol_list1 = (
+      # File with two symbols, same address.
+      ( 'sym1', 'r', 8, '/file', 0x1 ),
+      ( 'sym2', 'r', 8, '/file', 0x1 ),
+    )
+
+    symbol_list2 = (
+      # File with two symbols, not the same address.
+      ( 'sym1', 'r', 8, '/file', 0x1 ),
+      ( 'sym2', 'r', 6, '/file', 0x2 ),
+    )
+
+    # Here we go
+    (added, removed, changed, unchanged) = \
+        explain_binary_size_delta.Compare(symbol_list1, symbol_list2)
+
+
+    # Now check final stats.
+    orig_stdout = sys.stdout
+    output_collector = cStringIO.StringIO()
+    sys.stdout = output_collector
+    try:
+      explain_binary_size_delta.CrunchStats(added, removed, changed,
+                                            unchanged, True, True)
+    finally:
+      sys.stdout = orig_stdout
+    result = output_collector.getvalue()
+
+    expected_output = """\
+Total change: +6 bytes
+======================
+  2 grown, for a net change of +6 bytes (8 bytes before, 14 bytes after) \
+across 1 sources
+  0 unchanged, totalling 0 bytes
+Source stats:
+  1 sources encountered.
+  0 completely new.
+  0 removed completely.
+  1 partially changed.
+  0 completely unchanged.
+Per-source Analysis:
+
+----------------------------------------
+ +6 - Source: /file - (gained 6, lost 0)
+----------------------------------------
+  Grown symbols:
+         +4: sym1 type=r, (was 4 bytes, now 8 bytes) (adjusted sizes because \
+of memory sharing)
+         +2: sym2 type=r, (was 4 bytes, now 6 bytes) (adjusted sizes because \
+of memory sharing)
+"""
+
+    self.maxDiff = None
+    self.assertMultiLineEqual(expected_output, result)
+
+  def testCompareSymbolsBecomingUnshared(self):
+    # List entries have form:
+    # symbol_name, symbol_type, symbol_size, file_path, memory_address
+    symbol_list1 = (
+      # File with two symbols, not the same address.
+      ( 'sym1', 'r', 8, '/file', 0x1 ),
+      ( 'sym2', 'r', 6, '/file', 0x2 ),
+    )
+
+    symbol_list2 = (
+      # File with two symbols, same address.
+      ( 'sym1', 'r', 8, '/file', 0x1 ),
+      ( 'sym2', 'r', 8, '/file', 0x1 ),
+    )
+
+    # Here we go
+    (added, removed, changed, unchanged) = \
+        explain_binary_size_delta.Compare(symbol_list1, symbol_list2)
+
+
+    # Now check final stats.
+    orig_stdout = sys.stdout
+    output_collector = cStringIO.StringIO()
+    sys.stdout = output_collector
+    try:
+      explain_binary_size_delta.CrunchStats(added, removed, changed,
+                                            unchanged, True, True)
+    finally:
+      sys.stdout = orig_stdout
+    result = output_collector.getvalue()
+
+    expected_output = """\
+Total change: -6 bytes
+======================
+  2 shrunk, for a net change of -6 bytes (14 bytes before, 8 bytes after) \
+across 1 sources
+  0 unchanged, totalling 0 bytes
+Source stats:
+  1 sources encountered.
+  0 completely new.
+  0 removed completely.
+  1 partially changed.
+  0 completely unchanged.
+Per-source Analysis:
+
+----------------------------------------
+ -6 - Source: /file - (gained 0, lost 6)
+----------------------------------------
+  Shrunk symbols:
+         -2: sym2 type=r, (was 6 bytes, now 4 bytes) (adjusted sizes because \
+of memory sharing)
+         -4: sym1 type=r, (was 8 bytes, now 4 bytes) (adjusted sizes because \
+of memory sharing)
+"""
+
+    self.maxDiff = None
+    self.assertMultiLineEqual(expected_output, result)
+
+  def testDeltaInfo(self):
+    x = explain_binary_size_delta.DeltaInfo("path", "t", "sym_name", False)
+    assert x == x
+    y = explain_binary_size_delta.DeltaInfo("path", "t", "sym_name", False)
+    assert x == y
+
+    y.new_size = 12
+    assert x != y
+
+    x.new_size = 12
+    assert x == y
+
+    z = explain_binary_size_delta.DeltaInfo("path", "t", "sym_name", True)
+    assert not (x == z)
+    assert x != z
+
+    w = explain_binary_size_delta.DeltaInfo("other_path", "t", "sym_name", True)
+    assert w != z
 
 if __name__ == '__main__':
   unittest.main()