Use --data-file to configure the coverage database

Request by maintainer.

coverage/cmdline.py

@@ -125,12 +125,12 @@ class Opts:
         help="Write the JSON report to this file. Defaults to 'coverage.json'",
     )
     output_coverage = optparse.make_option(
-        '-o', '', action='store', dest="output_coverage",
+        '', '--data-file', action='store', dest="output_coverage",
         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",
+        '', '--data-file', 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'"

tests/test_cmdline.py

@@ -307,7 +307,7 @@ def test_erase(self):
             cov = Coverage()
             cov.erase()
             """)
-        self.cmd_executes("erase -c foo.cov", """\
+        self.cmd_executes("erase --data-file=foo.cov", """\
             cov = Coverage(data_file="foo.cov")
             cov.erase()
             """)
@@ -521,7 +521,7 @@ def test_report(self):
             cov.load()
             cov.report(sort='-foo')
             """)
-        self.cmd_executes("report -c foo.cov.2", """\
+        self.cmd_executes("report --data-file=foo.cov.2", """\
             cov = Coverage(data_file="foo.cov.2")
             cov.load()
             cov.report(show_missing=None)
@@ -652,7 +652,7 @@ def test_run(self):
             cov.stop()
             cov.save()
             """)
-        self.cmd_executes("run -o output.coverage foo.py", """\
+        self.cmd_executes("run --data-file=output.coverage foo.py", """\
             cov = Coverage(data_file="output.coverage")
             runner = PyRunner(['foo.py'], as_module=False)
             runner.prepare()