test: adapt to pytest assertion messages

Bare "assert" statements don't produce the same assertion message as
self.assertEqual did: they don't include the two values compared.  For
some of our own asserts, add back the detailed message.  For some checks
of asserts, it's fine that the values are missing because the longer
messsage includes the information.

2 files changed, 10 insertions, 10 deletions

diff --git a/tests/coveragetest.py b/tests/coveragetest.py
index ed3f1839..2e6f1323 100644
--- a/tests/coveragetest.py
+++ b/tests/coveragetest.py
@@ -198,7 +198,7 @@ class CoverageTest(
             if isinstance(lines[0], int):
                 # lines is just a list of numbers, it must match the statements
                 # found in the code.
-                assert statements == lines
+                assert statements == lines, "{!r} != {!r}".format(statements, lines)
             else:
                 # lines is a list of possible line number lists, one of them
                 # must match.
@@ -210,7 +210,7 @@ class CoverageTest(
 
             missing_formatted = analysis.missing_formatted()
             if isinstance(missing, string_class):
-                assert missing_formatted == missing
+                assert missing_formatted == missing, "{!r} != {!r}".format(missing_formatted, missing)
             else:
                 for missing_list in missing:
                     if missing_formatted == missing_list:
@@ -244,7 +244,7 @@ class CoverageTest(
             frep = StringIO()
             cov.report(mod, file=frep, show_missing=True)
             rep = " ".join(frep.getvalue().split("\n")[2].split()[1:])
-            assert report == rep
+            assert report == rep, "{!r} != {!r}".format(report, rep)
 
         return cov
 
@@ -351,7 +351,7 @@ class CoverageTest(
 
         """
         ret_actual = command_line(args)
-        assert ret_actual == ret
+        assert ret_actual == ret, "{!r} != {!r}".format(ret_actual, ret)
 
     # Some distros rename the coverage command, and need a way to indicate
     # their new command name to the tests. This is here for them to override,
diff --git a/tests/test_testing.py b/tests/test_testing.py
index 52560a5f..21e09dcc 100644
--- a/tests/test_testing.py
+++ b/tests/test_testing.py
@@ -48,10 +48,10 @@ class CoverageTestTest(CoverageTest):
         self.make_file("whoville.txt", "We are here!")
         self.assert_exists("whoville.txt")
         self.assert_doesnt_exist("shadow.txt")
-        msg = "False is not true : File 'whoville.txt' shouldn't exist"
+        msg = "File 'whoville.txt' shouldn't exist"
         with pytest.raises(AssertionError, match=msg):
             self.assert_doesnt_exist("whoville.txt")
-        msg = "False is not true : File 'shadow.txt' should exist"
+        msg = "File 'shadow.txt' should exist"
         with pytest.raises(AssertionError, match=msg):
             self.assert_exists("shadow.txt")
 
@@ -64,25 +64,25 @@ class CoverageTestTest(CoverageTest):
         self.assert_file_count("afile.*", 1)
         self.assert_file_count("*.q", 0)
         msg = re.escape(
-            "3 != 13 : There should be 13 files matching 'a*.txt', but there are these: "
+            "There should be 13 files matching 'a*.txt', but there are these: "
             "['abcde.txt', 'afile.txt', 'axczz.txt']"
         )
         with pytest.raises(AssertionError, match=msg):
             self.assert_file_count("a*.txt", 13)
         msg = re.escape(
-            "2 != 12 : There should be 12 files matching '*c*.txt', but there are these: "
+            "There should be 12 files matching '*c*.txt', but there are these: "
             "['abcde.txt', 'axczz.txt']"
         )
         with pytest.raises(AssertionError, match=msg):
             self.assert_file_count("*c*.txt", 12)
         msg = re.escape(
-            "1 != 11 : There should be 11 files matching 'afile.*', but there are these: "
+            "There should be 11 files matching 'afile.*', but there are these: "
             "['afile.txt']"
         )
         with pytest.raises(AssertionError, match=msg):
             self.assert_file_count("afile.*", 11)
         msg = re.escape(
-            "0 != 10 : There should be 10 files matching '*.q', but there are these: []"
+            "There should be 10 files matching '*.q', but there are these: []"
         )
         with pytest.raises(AssertionError, match=msg):
             self.assert_file_count("*.q", 10)