add command line option to show current configuration

coverage/cmdline.py

@@ -114,6 +114,10 @@ class Opts(object):
         '--show-contexts', action='store_true',
         help="Show contexts for covered lines.",
     )
+    show_omit = optparse.make_option(
+        '--show-omit', action='store_true',
+        help="Show omit entries in coverage config files.",
+    )
     omit = optparse.make_option(
         '', '--omit', action='store',
         metavar="PAT1,PAT2,...",
@@ -212,6 +216,7 @@ def __init__(self, *args, **kwargs):
             append=None,
             branch=None,
             concurrency=None,
+            config=None,
             context=None,
             debug=None,
             directory=None,
@@ -231,6 +236,7 @@ def __init__(self, *args, **kwargs):
             skip_covered=None,
             skip_empty=None,
             show_contexts=None,
+            show_omit=None,
             sort=None,
             source=None,
             timid=None,
@@ -351,6 +357,20 @@ def get_prog_name(self):
         ),
     ),
 
+    'config': CmdOptionParser(
+        "config",
+        [
+            Opts.show_omit,
+            Opts.output_json,
+        ] + GLOBAL_ARGS,
+        usage="[options] [modules]",
+        description=(
+            "Get current configuration. "
+            "Topics are: "
+                "'omit' to show configuration omit entries in list format; "
+        ),
+    ),
+
     'debug': CmdOptionParser(
         "debug", GLOBAL_ARGS,
         usage="<topic>",
@@ -610,6 +630,18 @@ def command_line(self, argv):
 
         self.coverage.load()
 
+        if options.action == "config":
+            # Allows end user to see omit settings
+            # Useful since there are several configuration files in many different formats
+            # Which do environment variable expansion, etc
+            if options.show_omit:
+                if options.outfile == "json":
+                    print(self.coverage.config.run_omit)
+                else:
+                    joined_string = ",".join(self.coverage.config.run_omit)
+                    print(joined_string)
+            return OK
+
         total = None
         if options.action == "report":
             total = self.coverage.report(

tests/test_cmdline.py

@@ -34,6 +34,9 @@ class BaseCmdLineTest(CoverageTest):
         directory=None, ignore_errors=None, include=None, omit=None, morfs=[],
         contexts=None,
     )
+    _defaults.Coverage().config(
+        show_omit=None, json=None
+    )
     _defaults.Coverage().html_report(
         directory=None, ignore_errors=None, include=None, omit=None, morfs=[],
         skip_covered=None, show_contexts=None, title=None, contexts=None,
@@ -252,6 +255,11 @@ def test_debug(self):
         self.cmd_help("debug", "What information would you like: config, data, sys, premain?")
         self.cmd_help("debug foo", "Don't know what you mean by 'foo'")
 
+    def test_config(self):
+        self.command_line("config")
+        out = self.stdout()
+        assert "" in out
+
     def test_debug_sys(self):
         self.command_line("debug sys")
         out = self.stdout()