Add an input coverage option to report commands

-o for coverage run is not very useful if the commands that consume
coverage and generate reports/coverage (json/xml/html/combine ...) can't
take that file as input, so add a -c/--input-coverage option for these
commands.

Author: nbfalcon

coverage/cmdline.py

@@ -129,6 +129,12 @@ class Opts:
         metavar="OUTFILE",
         help="Write the recorded coverage information to this file. Defaults to '.coverage'"
     )
+    input_coverage = optparse.make_option(
+        '-c', '--input-coverage', action='store', dest="input_coverage",
+        metavar="INPUT",
+        help="Read coverage data for report generation from this file (needed if you have "
+             "specified -o previously). Defaults to '.coverage'"
+    )
     json_pretty_print = optparse.make_option(
         '', '--pretty-print', action='store_true',
         help="Format the JSON for human readers.",
@@ -326,6 +332,8 @@ def get_prog_name(self):
     Opts.rcfile,
     ]
 
+REPORT_ARGS = [Opts.input_coverage]
+
 CMDS = {
     'annotate': CmdOptionParser(
         "annotate",
@@ -334,7 +342,7 @@ def get_prog_name(self):
             Opts.ignore_errors,
             Opts.include,
             Opts.omit,
-            ] + GLOBAL_ARGS,
+            ] + REPORT_ARGS + GLOBAL_ARGS,
         usage="[options] [modules]",
         description=(
             "Make annotated copies of the given files, marking statements that are executed " +
@@ -348,6 +356,7 @@ def get_prog_name(self):
             Opts.append,
             Opts.keep,
             Opts.quiet,
+            Opts.output_coverage
             ] + GLOBAL_ARGS,
         usage="[options] <path1> <path2> ... <pathN>",
         description=(
@@ -401,7 +410,7 @@ def get_prog_name(self):
             Opts.no_skip_covered,
             Opts.skip_empty,
             Opts.title,
-            ] + GLOBAL_ARGS,
+            ] + REPORT_ARGS + GLOBAL_ARGS,
         usage="[options] [modules]",
         description=(
             "Create an HTML report of the coverage of the files.  " +
@@ -422,7 +431,7 @@ def get_prog_name(self):
             Opts.json_pretty_print,
             Opts.quiet,
             Opts.show_contexts,
-            ] + GLOBAL_ARGS,
+            ] + REPORT_ARGS + GLOBAL_ARGS,
         usage="[options] [modules]",
         description="Generate a JSON report of coverage results."
     ),
@@ -441,7 +450,7 @@ def get_prog_name(self):
             Opts.skip_covered,
             Opts.no_skip_covered,
             Opts.skip_empty,
-            ] + GLOBAL_ARGS,
+            ] + REPORT_ARGS + GLOBAL_ARGS,
         usage="[options] [modules]",
         description="Report coverage statistics on modules."
     ),
@@ -476,7 +485,7 @@ def get_prog_name(self):
             Opts.output_xml,
             Opts.quiet,
             Opts.skip_empty,
-            ] + GLOBAL_ARGS,
+            ] + REPORT_ARGS + GLOBAL_ARGS,
         usage="[options] [modules]",
         description="Generate an XML report of coverage results."
     ),
@@ -579,8 +588,7 @@ def command_line(self, argv):
         else:
             concurrency = None
 
-        data_file = options.outfile if options.action in ["run", "combine"] \
-            else getattr(options, "input_coverage", None)
+        data_file = options.outfile if options.action == "run" else None
         # Do something.
         self.coverage = Coverage(
             data_file=data_file or DEFAULT_DATAFILE,

tests/test_cmdline.py

@@ -247,6 +247,11 @@ def test_combine(self):
             cov.combine(None, strict=True, keep=False)
             cov.save()
             """)
+        self.cmd_executes("combine -o foo.cov", """\
+            cov = Coverage(data_file="foo.cov")
+            cov.combine(None, strict=True, keep=False)
+            cov.save()
+            """)
 
     def test_combine_doesnt_confuse_options_with_args(self):
         # https://github.com/nedbat/coveragepy/issues/385
@@ -512,6 +517,11 @@ def test_report(self):
             cov.load()
             cov.report(sort='-foo')
             """)
+        self.cmd_executes("report -c foo.cov.2", """\
+            cov = Coverage(data_file="foo.cov.2")
+            cov.load()
+            cov.report(show_missing=None)
+            """)
 
     def test_run(self):
         # coverage run [-p] [-L] [--timid] MODULE.py [ARG1 ARG2 ...]