Attempt to add a mechanism for tagging hooks

tests/commands/run_test.py

@@ -144,12 +144,14 @@ def _do_run(cap_out, store, repo, args, environ={}, config_file=C.CONFIG_FILE):
 
 def _test_run(
     cap_out, store, repo, opts, expected_outputs, expected_ret, stage,
-    config_file=C.CONFIG_FILE,
+    config_file=C.CONFIG_FILE, environ_override=None
 ):
     if stage:
         stage_a_file()
+    if environ_override is None:
+        environ_override = {}
     args = run_opts(**opts)
-    ret, printed = _do_run(cap_out, store, repo, args, config_file=config_file)
+    ret, printed = _do_run(cap_out, store, repo, args, config_file=config_file, environ=environ_override)
 
     assert ret == expected_ret, (ret, expected_ret, printed)
     for expected_output_part in expected_outputs:
@@ -352,6 +354,7 @@ def test_show_diff_on_failure(
         ({}, (b'Bash hook', b'Passed'), 0, True),
         ({'verbose': True}, (b'foo.py\nHello World',), 0, True),
         ({'hook': 'bash_hook'}, (b'Bash hook', b'Passed'), 0, True),
+        ({'tags': ['foo']}, (b'Bash hook', b'Passed'), 0, True),
         (
             {'hook': 'nope'},
             (b'No hook with id `nope` in stage `commit`',),
@@ -364,6 +367,18 @@ def test_show_diff_on_failure(
             1,
             True,
         ),
+        (
+            {'tags': ['bar', 'baz']},
+            (b'No hooks with tags matching `[\'bar\', \'baz\']` in stage `commit`',),
+            1,
+            True,
+        ),
+        (
+            {'tags': ['bar', 'baz'], 'hook_stage': 'push'},
+            (b'No hooks with tags matching `[\'bar\', \'baz\']` in stage `push`',),
+            1,
+            True,
+        ),
         (
             {'all_files': True, 'verbose': True},
             (b'foo.py',),
@@ -618,6 +633,18 @@ def test_skip_aliased_hook(cap_out, store, aliased_repo):
     for msg in (b'Bash hook', b'Skipped'):
         assert printed.count(msg) == 1
 
+def test_skip_tag(cap_out, store, repo_with_passing_hook):
+    _test_run(
+        cap_out,
+        store,
+        repo_with_passing_hook,
+        {},
+        (b'Bash hook', b'Skipped'),
+        0,
+        True,
+        environ_override={'SKIP': 'foo'}
+    )
+
 
 def test_skip_bypasses_installation(cap_out, store, repo_with_passing_hook):
     config = {