adjust error outputs to be more standardized

tests/check_docstring_first_test.py

@@ -17,7 +17,7 @@ TESTS = (
         b'from __future__ import unicode_literals\n'
         b'"foo"\n',
         1,
-        '{filename}:2 Module docstring appears after code '
+        '{filename}:2: Module docstring appears after code '
         '(code seen on line 1).\n',
     ),
     # Test double docstring
@@ -26,7 +26,7 @@ TESTS = (
         b'from __future__ import absolute_import\n'
         b'"fake docstring"\n',
         1,
-        '{filename}:3 Multiple module docstrings '
+        '{filename}:3: Multiple module docstrings '
         '(first docstring on line 1).\n',
     ),
     # Test multiple lines of code above
@@ -35,7 +35,7 @@ TESTS = (
         b'import sys\n'
         b'"docstring"\n',
         1,
-        '{filename}:3 Module docstring appears after code '
+        '{filename}:3: Module docstring appears after code '
         '(code seen on line 1).\n',
     ),
     # String literals in expressions are ok.

tests/check_merge_conflict_test.py

@@ -101,8 +101,14 @@ def repository_pending_merge(tmpdir):
 
 
 @pytest.mark.usefixtures('f1_is_a_conflict_file')
-def test_merge_conflicts_git():
+def test_merge_conflicts_git(capsys):
     assert main(['f1']) == 1
+    out, _ = capsys.readouterr()
+    assert out == (
+        "f1:1: Merge conflict string '<<<<<<<' found\n"
+        "f1:3: Merge conflict string '=======' found\n"
+        "f1:5: Merge conflict string '>>>>>>>' found\n"
+    )
 
 
 @pytest.mark.parametrize(
@@ -139,7 +145,7 @@ def test_care_when_assumed_merge(tmpdir):
     assert main([str(f.realpath()), '--assume-in-merge']) == 1
 
 
-def test_worktree_merge_conflicts(f1_is_a_conflict_file, tmpdir):
+def test_worktree_merge_conflicts(f1_is_a_conflict_file, tmpdir, capsys):
     worktree = tmpdir.join('worktree')
     cmd_output('git', 'worktree', 'add', str(worktree))
     with worktree.as_cwd():
@@ -148,4 +154,4 @@ def test_worktree_merge_conflicts(f1_is_a_conflict_file, tmpdir):
         )
         msg = f1_is_a_conflict_file.join('.git/worktrees/worktree/MERGE_MSG')
         assert msg.exists()
-        test_merge_conflicts_git()
+        test_merge_conflicts_git(capsys)

tests/debug_statement_hook_test.py

@@ -55,7 +55,9 @@ def test_non_utf8_file(tmpdir):
     assert main((str(f_py),)) == 0
 
 
-def test_py37_breakpoint(tmpdir):
+def test_py37_breakpoint(tmpdir, capsys):
     f_py = tmpdir.join('f.py')
     f_py.write('def f():\n    breakpoint()\n')
     assert main((str(f_py),)) == 1
+    out, _ = capsys.readouterr()
+    assert out == f'{f_py}:2:4: breakpoint called\n'