fix: lcov command didn't report a total, so --fail-under didn't work

Author: nedbat

CHANGES.rst

@@ -30,6 +30,9 @@ Unreleased
 
 - Fix: adjusted how decorators are traced on PyPy 7.3.10, fixing `issue 1515`_.
 
+- Fix: the ``coverage lcov`` report did not properly implement the
+  ``--fail-under=MIN`` option.  This has been fixed.
+
 - Refactor: a number of refactorings internally due to adding type annotations.
   This should not affect outward behavior, but they were a bit invasive in some
   places.

coverage/lcovreport.py

@@ -8,6 +8,7 @@
 from hashlib import md5
 
 from coverage.report import get_analysis_to_report
+from coverage.results import Analysis, Numbers
 
 
 class LcovReporter:
@@ -17,7 +18,7 @@ class LcovReporter:
 
     def __init__(self, coverage):
         self.coverage = coverage
-        self.config = self.coverage.config
+        self.total = Numbers(self.coverage.config.precision)
 
     def report(self, morfs, outfile=None):
         """Renders the full lcov report.
@@ -33,12 +34,16 @@ def report(self, morfs, outfile=None):
         for fr, analysis in get_analysis_to_report(self.coverage, morfs):
             self.get_lcov(fr, analysis, outfile)
 
+        return self.total.n_statements and self.total.pc_covered
+
     def get_lcov(self, fr, analysis, outfile=None):
         """Produces the lcov data for a single file.
 
         This currently supports both line and branch coverage,
         however function coverage is not supported.
         """
+        self.total += analysis.numbers
+
         outfile.write("TN:\n")
         outfile.write(f"SF:{fr.relative_filename()}\n")
         source_lines = fr.source().splitlines()

tests/test_lcov.py

@@ -3,6 +3,7 @@
 
 """Test LCOV-based summary reporting for coverage.py."""
 
+import math
 import textwrap
 
 from tests.coveragetest import CoverageTest
@@ -75,7 +76,8 @@ def IsItTrue():
         self.assert_doesnt_exist(".coverage")
         cov = coverage.Coverage(source=["."])
         self.start_import_stop(cov, "main_file")
-        cov.lcov_report()
+        pct = cov.lcov_report()
+        assert pct == 50.0
         actual_result = self.get_lcov_report_content()
         assert expected_result == actual_result
 
@@ -87,7 +89,8 @@ def test_simple_line_coverage_two_files(self):
         self.make_file(".coveragerc", "[lcov]\noutput = data.lcov\n")
         cov = coverage.Coverage(source=".")
         self.start_import_stop(cov, "test_file")
-        cov.lcov_report()
+        pct = cov.lcov_report()
+        assert pct == 50.0
         self.assert_exists("data.lcov")
         expected_result = textwrap.dedent("""\
             TN:
@@ -130,7 +133,8 @@ def is_it_x(x):
         self.assert_doesnt_exist(".coverage")
         cov = coverage.Coverage(branch=True, source=".")
         self.start_import_stop(cov, "main_file")
-        cov.lcov_report()
+        pct = cov.lcov_report()
+        assert math.isclose(pct, 16.666666666666668)
         self.assert_exists("coverage.lcov")
         expected_result = textwrap.dedent("""\
             TN:
@@ -177,7 +181,8 @@ def test_is_it_x(self):
         self.assert_doesnt_exist(".coverage")
         cov = coverage.Coverage(branch=True, source=".")
         self.start_import_stop(cov, "test_file")
-        cov.lcov_report()
+        pct = cov.lcov_report()
+        assert math.isclose(pct, 41.666666666666664)
         self.assert_exists("coverage.lcov")
         expected_result = textwrap.dedent("""\
             TN:
@@ -225,7 +230,8 @@ def test_half_covered_branch(self):
         self.assert_doesnt_exist(".coverage")
         cov = coverage.Coverage(branch=True, source=".")
         self.start_import_stop(cov, "main_file")
-        cov.lcov_report()
+        pct = cov.lcov_report()
+        assert math.isclose(pct, 66.66666666666667)
         self.assert_exists("coverage.lcov")
         expected_result = textwrap.dedent("""\
             TN:
@@ -259,7 +265,8 @@ def test_empty_init_files(self):
         self.assert_doesnt_exist(".coverage")
         cov = coverage.Coverage(branch=True, source=".")
         self.start_import_stop(cov, "__init__")
-        cov.lcov_report()
+        pct = cov.lcov_report()
+        assert pct == 0.0
         self.assert_exists("coverage.lcov")
         # Newer Pythons have truly empty empty files.
         if env.PYBEHAVIOR.empty_is_empty: