style: a bit of refactoring for lcov code

2 files changed, 29 insertions, 27 deletions

diff --git a/coverage/lcovreport.py b/coverage/lcovreport.py
index a4ad9cd9..8e3a5768 100644
--- a/coverage/lcovreport.py
+++ b/coverage/lcovreport.py
@@ -5,9 +5,9 @@
 
 from __future__ import annotations
 
-import sys
 import base64
-from hashlib import md5
+import hashlib
+import sys
 
 from typing import IO, Iterable, Optional, TYPE_CHECKING
 
@@ -20,6 +20,12 @@ if TYPE_CHECKING:
     from coverage import Coverage
 
 
+def line_hash(line: str) -> str:
+    """Produce a hash of a source line for use in the LCOV file."""
+    hashed = hashlib.md5(line.encode("utf-8")).digest()
+    return base64.b64encode(hashed).decode("ascii").rstrip("=")
+
+
 class LcovReporter:
     """A reporter for writing LCOV coverage reports."""
 
@@ -68,17 +74,15 @@ class LcovReporter:
             # 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]
             else:
-                line = b""
-            hashed = base64.b64encode(md5(line).digest()).decode().rstrip("=")
-            outfile.write(f"DA:{covered},1,{hashed}\n")
+                line = ""
+            outfile.write(f"DA:{covered},1,{line_hash(line)}\n")
 
         for missed in sorted(analysis.missing):
             assert source_lines
-            line = source_lines[missed-1].encode("utf-8")
-            hashed = base64.b64encode(md5(line).digest()).decode().rstrip("=")
-            outfile.write(f"DA:{missed},0,{hashed}\n")
+            line = source_lines[missed-1]
+            outfile.write(f"DA:{missed},0,{line_hash(line)}\n")
 
         outfile.write(f"LF:{analysis.numbers.n_statements}\n")
         outfile.write(f"LH:{analysis.numbers.n_executed}\n")
diff --git a/tests/test_lcov.py b/tests/test_lcov.py
index 6d50b62b..b7533c89 100644
--- a/tests/test_lcov.py
+++ b/tests/test_lcov.py
@@ -52,8 +52,8 @@ class LcovTest(CoverageTest):
             return file.read()
 
     def test_lone_file(self) -> None:
-        """For a single file with a couple of functions, the lcov should cover
-        the function definitions themselves, but not the returns."""
+        # For a single file with a couple of functions, the lcov should cover
+        # the function definitions themselves, but not the returns.
         self.make_file("main_file.py", """\
             #!/usr/bin/env python3
 
@@ -83,8 +83,8 @@ class LcovTest(CoverageTest):
         assert expected_result == actual_result
 
     def test_simple_line_coverage_two_files(self) -> None:
-        """Test that line coverage is created when coverage is run,
-        and matches the output of the file below."""
+        # Test that line coverage is created when coverage is run,
+        # and matches the output of the file below.
         self.create_initial_files()
         self.assert_doesnt_exist(".coverage")
         self.make_file(".coveragerc", "[lcov]\noutput = data.lcov\n")
@@ -121,7 +121,7 @@ class LcovTest(CoverageTest):
         assert expected_result == actual_result
 
     def test_branch_coverage_one_file(self) -> None:
-        """Test that the reporter produces valid branch coverage."""
+        # Test that the reporter produces valid branch coverage.
         self.make_file("main_file.py", """\
             #!/usr/bin/env python3
 
@@ -156,8 +156,8 @@ class LcovTest(CoverageTest):
         assert expected_result == actual_result
 
     def test_branch_coverage_two_files(self) -> None:
-        """Test that valid branch coverage is generated
-        in the case of two files."""
+        # Test that valid branch coverage is generated
+        # in the case of two files.
         self.make_file("main_file.py", """\
             #!/usr/bin/env python3
 
@@ -217,9 +217,8 @@ class LcovTest(CoverageTest):
         assert actual_result == expected_result
 
     def test_half_covered_branch(self) -> None:
-        """Test that for a given branch that is only half covered,
-        the block numbers remain the same, and produces valid lcov.
-        """
+        # Test that for a given branch that is only half covered,
+        # the block numbers remain the same, and produces valid lcov.
         self.make_file("main_file.py", """\
             something = True
 
@@ -253,14 +252,13 @@ class LcovTest(CoverageTest):
         assert actual_result == expected_result
 
     def test_empty_init_files(self) -> None:
-        """Test that in the case of an empty __init__.py file, the lcov
-        reporter will note that the file is there, and will note the empty
-        line. It will also note the lack of branches, and the checksum for
-        the line.
-
-        Although there are no lines found, it will note one line as hit in
-        old Pythons, and no lines hit in newer Pythons.
-        """
+        # Test that in the case of an empty __init__.py file, the lcov
+        # reporter will note that the file is there, and will note the empty
+        # line. It will also note the lack of branches, and the checksum for
+        # the line.
+        #
+        # Although there are no lines found, it will note one line as hit in
+        # old Pythons, and no lines hit in newer Pythons.
 
         self.make_file("__init__.py", "")
         self.assert_doesnt_exist(".coverage")