style: cleanups after lcov, though more than just lcov

CHANGES.rst

@@ -23,7 +23,7 @@ Unreleased
 ----------
 
 - Feature: Added the `lcov` command to generate reports in LCOV format.
-  Thanks, Bradley Burns.
+  Thanks, Bradley Burns. Closes `issue 587`_ and `issue 626`_.
 
 - Dropped support for Python 3.6, which reached end-of-life on 2021-12-23.
 
@@ -39,6 +39,8 @@ Unreleased
 
 - Releases now have MacOS arm64 wheels for Apple Silicon (fixes `issue 1288`_).
 
+.. _issue 587: https://github.com/nedbat/coveragepy/issues/587
+.. _issue 626: https://github.com/nedbat/coveragepy/issues/626
 .. _issue 883: https://github.com/nedbat/coveragepy/issues/883
 .. _issue 1288: https://github.com/nedbat/coveragepy/issues/1288
 .. _issue 1294: https://github.com/nedbat/coveragepy/issues/1294

coverage/cmdline.py

@@ -123,15 +123,15 @@ class Opts:
         metavar="OUTFILE",
         help="Write the JSON report to this file. Defaults to 'coverage.json'",
     )
+    output_lcov = optparse.make_option(
+        '-o', '', action='store', dest='outfile',
+        metavar="OUTFILE",
+        help="Write the LCOV report to this file. Defaults to 'coverage.lcov'",
+    )
     json_pretty_print = optparse.make_option(
         '', '--pretty-print', action='store_true',
         help="Format the JSON for human readers.",
     )
-    lcov = optparse.make_option(
-        '-o', '', action='store', dest='outfile',
-        metavar="OUTFILE",
-        help="Write the LCOV report to this file. Defaults to 'coverage.lcov'"
-    )
     parallel_mode = optparse.make_option(
         '-p', '--parallel-mode', action='store_true',
         help=(
@@ -423,7 +423,21 @@ def get_prog_name(self):
             Opts.show_contexts,
             ] + GLOBAL_ARGS,
         usage="[options] [modules]",
-        description="Generate a JSON report of coverage results."
+        description="Generate a JSON report of coverage results.",
+    ),
+
+    'lcov': CmdOptionParser(
+        "lcov",
+        [
+            Opts.fail_under,
+            Opts.ignore_errors,
+            Opts.include,
+            Opts.output_lcov,
+            Opts.omit,
+            Opts.quiet,
+        ] + GLOBAL_ARGS,
+        usage="[options] [modules]",
+        description="Generate an LCOV report of coverage results.",
     ),
 
     'report': CmdOptionParser(
@@ -442,7 +456,7 @@ def get_prog_name(self):
             Opts.skip_empty,
             ] + GLOBAL_ARGS,
         usage="[options] [modules]",
-        description="Report coverage statistics on modules."
+        description="Report coverage statistics on modules.",
     ),
 
     'run': CmdOptionParser(
@@ -461,7 +475,7 @@ def get_prog_name(self):
             Opts.timid,
             ] + GLOBAL_ARGS,
         usage="[options] <pyfile> [program options]",
-        description="Run a Python program, measuring code execution."
+        description="Run a Python program, measuring code execution.",
     ),
 
     'xml': CmdOptionParser(
@@ -476,22 +490,8 @@ def get_prog_name(self):
             Opts.skip_empty,
             ] + GLOBAL_ARGS,
         usage="[options] [modules]",
-        description="Generate an XML report of coverage results."
+        description="Generate an XML report of coverage results.",
     ),
-
-    'lcov': CmdOptionParser(
-        "lcov",
-        [
-            Opts.fail_under,
-            Opts.ignore_errors,
-            Opts.include,
-            Opts.lcov,
-            Opts.omit,
-            Opts.quiet,
-        ] + GLOBAL_ARGS,
-        usage="[options] [modules]",
-        description="Generate an LCOV report of coverage results."
-    )
 }
 
 
@@ -681,7 +681,6 @@ def command_line(self, argv):
                 outfile=options.outfile,
                 **report_args
                 )
-
         else:
             # There are no other possible actions.
             raise AssertionError
@@ -876,10 +875,10 @@ def unglob_args(args):
             help        Get help on using coverage.py.
             html        Create an HTML report.
             json        Create a JSON report of coverage results.
+            lcov        Create an LCOV report of coverage results.
             report      Report coverage stats on modules.
             run         Run a Python program and measure code execution.
             xml         Create an XML report of coverage results.
-            lcov        Create an LCOV report of coverage results.
 
         Use "{program_name} help <command>" for detailed help on any command.
     """,

coverage/lcovreport.py

@@ -20,7 +20,7 @@ def __init__(self, coverage):
         self.config = self.coverage.config
 
     def report(self, morfs, outfile=None):
-        """Renders the full lcov report
+        """Renders the full lcov report.
 
         'morfs' is a list of modules or filenames
 
@@ -34,41 +34,42 @@ def report(self, morfs, outfile=None):
             self.get_lcov(fr, analysis, outfile)
 
     def get_lcov(self, fr, analysis, outfile=None):
-        """Produces the lcov data for a single file
+        """Produces the lcov data for a single file.
 
-        get_lcov currently supports both line and branch coverage,
+        This currently supports both line and branch coverage,
         however function coverage is not supported.
-
         """
-
         outfile.write("TN:\n")
         outfile.write(f"SF:{fr.relative_filename()}\n")
         source_lines = fr.source().splitlines()
+
         for covered in sorted(analysis.executed):
-            # Note: Coveragepy currently only supports checking *if* a line has
-            # been executed, not how many times, so we set this to 1 for nice
-            # output even if it's technically incorrect
-
-            # The lines below calculate a 64 bit encoded md5 hash of the line
-            # corresponding to the DA lines in the lcov file,
-            # for either case of the line being covered or missed in Coveragepy
-            # The final two characters of the encoding ("==") are removed from
-            # the hash to allow genhtml to run on the resulting lcov file
+            # Note: Coverage.py currently only supports checking *if* a line
+            # has been executed, not how many times, so we set this to 1 for
+            # nice output even if it's technically incorrect.
+
+            # The lines below calculate a 64-bit encoded md5 hash of the line
+            # corresponding to the DA lines in the lcov file, for either case
+            # of the line being covered or missed in coverage.py. The final two
+            # characters of the encoding ("==") are removed from the hash to
+            # allow genhtml to run on the resulting lcov file.
             if source_lines:
-                line = source_lines[covered - 1].encode("utf-8")
+                line = source_lines[covered-1].encode("utf-8")
             else:
                 line = b""
-            hashed = str(base64.b64encode(md5(line).digest())[:-2], encoding="utf-8")
+            hashed = base64.b64encode(md5(line).digest()).decode().rstrip("=")
             outfile.write(f"DA:{covered},1,{hashed}\n")
+
         for missed in sorted(analysis.missing):
             assert source_lines
             line = source_lines[missed-1].encode("utf-8")
-            hashed = str(base64.b64encode(md5(line).digest())[:-2], encoding="utf-8")
+            hashed = base64.b64encode(md5(line).digest()).decode().rstrip("=")
             outfile.write(f"DA:{missed},0,{hashed}\n")
+
         outfile.write(f"LF:{len(analysis.statements)}\n")
         outfile.write(f"LH:{len(analysis.executed)}\n")
 
-        # More information dense branch coverage data
+        # More information dense branch coverage data.
         missing_arcs = analysis.missing_branch_arcs()
         executed_arcs = analysis.executed_branch_arcs()
         for block_number, block_line_number in enumerate(
@@ -78,22 +79,23 @@ def get_lcov(self, fr, analysis, outfile=None):
                 sorted(missing_arcs[block_line_number])
             ):
                 # The exit branches have a negative line number,
-                # this will not produce valid lcov, and so setting
+                # this will not produce valid lcov. Setting
                 # the line number of the exit branch to 0 will allow
-                # for valid lcov, while preserving the data
+                # for valid lcov, while preserving the data.
                 line_number = max(line_number, 0)
                 outfile.write(f"BRDA:{line_number},{block_number},{branch_number},-\n")
+
             # The start value below allows for the block number to be
             # preserved between these two for loops (stopping the loop from
-            # resetting the value of the block number to 0)
+            # resetting the value of the block number to 0).
             for branch_number, line_number in enumerate(
                 sorted(executed_arcs[block_line_number]),
                 start=len(missing_arcs[block_line_number]),
             ):
                 line_number = max(line_number, 0)
                 outfile.write(f"BRDA:{line_number},{block_number},{branch_number},1\n")
 
-        # Summary of the branch coverage
+        # Summary of the branch coverage.
         if analysis.has_arcs():
             branch_stats = analysis.branch_stats()
             brf = sum(t for t, k in branch_stats.values())