Branch coverage

CONTRIBUTING.md

@@ -64,3 +64,16 @@ To run the end-to-end tests, you'll need:
 - Please be aware that the tests will launch `gh auth setup-git` which might be
   surprising if you use `https` remotes (sadly, setting `GIT_CONFIG_GLOBAL`
   seems not to be enough to isolate tests.)
+
+## Coverage labs
+
+### Computing the coverage rate
+
+The coverage rate is `covered_lines / total_lines` (as one would expect).
+In case "branch coverage" is enabled, the coverage rate is
+`(covered_lines + covered_branches) / (total_lines + total_branches)`.
+In order to display coverage rates, we need to round the values. Depending on
+the situation, we either round to 0 or 2 decimal places. Rounding rules are:
+- We always round down (truncate) the value.
+- We don't display the trailing zeros in the decimal part (nor the decimal point
+  if the decimal part is 0).

coverage_comment/coverage.py

@@ -6,6 +6,7 @@
 import json
 import pathlib
 from collections.abc import Sequence
+from typing import cast
 
 from coverage_comment import log, subprocess
 
@@ -28,10 +29,10 @@ class CoverageInfo:
     percent_covered: decimal.Decimal
     missing_lines: int
     excluded_lines: int
-    num_branches: int | None
-    num_partial_branches: int | None
-    covered_branches: int | None
-    missing_branches: int | None
+    num_branches: int = 0
+    num_partial_branches: int = 0
+    covered_branches: int = 0
+    missing_branches: int = 0
 
 
 @dataclasses.dataclass
@@ -41,6 +42,8 @@ class FileCoverage:
     missing_lines: list[int]
     excluded_lines: list[int]
     info: CoverageInfo
+    executed_branches: list[list[int]] | None = None
+    missing_branches: list[list[int]] | None = None
 
 
 @dataclasses.dataclass
@@ -82,10 +85,20 @@ class DiffCoverage:
     files: dict[pathlib.Path, FileDiffCoverage]
 
 
-def compute_coverage(num_covered: int, num_total: int) -> decimal.Decimal:
-    if num_total == 0:
+def compute_coverage(
+    num_covered: int,
+    num_total: int,
+    num_branches_covered: int = 0,
+    num_branches_total: int = 0,
+) -> decimal.Decimal:
+    """Compute the coverage percentage, with or without branch coverage."""
+    num_branches_covered = cast(int, num_branches_covered)
+    num_branches_total = cast(int, num_branches_total)
+    numerator = decimal.Decimal(num_covered + num_branches_covered)
+    denominator = decimal.Decimal(num_total + num_branches_total)
+    if denominator == 0:
         return decimal.Decimal("1")
-    return decimal.Decimal(num_covered) / decimal.Decimal(num_total)
+    return numerator / denominator
 
 
 def get_coverage_info(
@@ -138,6 +151,26 @@ def generate_coverage_markdown(coverage_path: pathlib.Path) -> str:
     )
 
 
+def _make_coverage_info(data: dict) -> CoverageInfo:
+    """Build a CoverageInfo object from a "summary" or "totals" key."""
+    return CoverageInfo(
+        covered_lines=data["covered_lines"],
+        num_statements=data["num_statements"],
+        percent_covered=compute_coverage(
+            num_covered=data["covered_lines"],
+            num_total=data["num_statements"],
+            num_branches_covered=data.get("covered_branches", 0),
+            num_branches_total=data.get("num_branches", 0),
+        ),
+        missing_lines=data["missing_lines"],
+        excluded_lines=data["excluded_lines"],
+        num_branches=data.get("num_branches"),
+        num_partial_branches=data.get("num_partial_branches"),
+        covered_branches=data.get("covered_branches", 0),
+        missing_branches=data.get("missing_branches", 0),
+    )
+
+
 def extract_info(data: dict, coverage_path: pathlib.Path) -> Coverage:
     """
     {
@@ -191,39 +224,13 @@ def extract_info(data: dict, coverage_path: pathlib.Path) -> Coverage:
                 excluded_lines=file_data["excluded_lines"],
                 executed_lines=file_data["executed_lines"],
                 missing_lines=file_data["missing_lines"],
-                info=CoverageInfo(
-                    covered_lines=file_data["summary"]["covered_lines"],
-                    num_statements=file_data["summary"]["num_statements"],
-                    percent_covered=compute_coverage(
-                        file_data["summary"]["covered_lines"],
-                        file_data["summary"]["num_statements"],
-                    ),
-                    missing_lines=file_data["summary"]["missing_lines"],
-                    excluded_lines=file_data["summary"]["excluded_lines"],
-                    num_branches=file_data["summary"].get("num_branches"),
-                    num_partial_branches=file_data["summary"].get(
-                        "num_partial_branches"
-                    ),
-                    covered_branches=file_data["summary"].get("covered_branches"),
-                    missing_branches=file_data["summary"].get("missing_branches"),
-                ),
+                executed_branches=file_data.get("executed_branches"),
+                missing_branches=file_data.get("missing_branches"),
+                info=_make_coverage_info(file_data["summary"]),
             )
             for path, file_data in data["files"].items()
         },
-        info=CoverageInfo(
-            covered_lines=data["totals"]["covered_lines"],
-            num_statements=data["totals"]["num_statements"],
-            percent_covered=compute_coverage(
-                data["totals"]["covered_lines"],
-                data["totals"]["num_statements"],
-            ),
-            missing_lines=data["totals"]["missing_lines"],
-            excluded_lines=data["totals"]["excluded_lines"],
-            num_branches=data["totals"].get("num_branches"),
-            num_partial_branches=data["totals"].get("num_partial_branches"),
-            covered_branches=data["totals"].get("covered_branches"),
-            missing_branches=data["totals"].get("missing_branches"),
-        ),
+        info=_make_coverage_info(data["totals"]),
     )
 
 
@@ -256,7 +263,8 @@ def get_diff_coverage_info(
         total_num_violations += count_missing
 
         percent_covered = compute_coverage(
-            num_covered=count_executed, num_total=count_total
+            num_covered=count_executed,
+            num_total=count_total,
         )
 
         files[path] = FileDiffCoverage(

tests/conftest.py

@@ -282,10 +282,10 @@ def _(code: str, has_branches: bool = True) -> coverage_module.Coverage:
                 percent_covered=decimal.Decimal("1.0"),
                 missing_lines=0,
                 excluded_lines=0,
-                num_branches=0 if has_branches else None,
-                num_partial_branches=0 if has_branches else None,
-                covered_branches=0 if has_branches else None,
-                missing_branches=0 if has_branches else None,
+                num_branches=0,
+                num_partial_branches=0,
+                covered_branches=0,
+                missing_branches=0,
             ),
             files={},
         )
@@ -313,10 +313,10 @@ def _(code: str, has_branches: bool = True) -> coverage_module.Coverage:
                         percent_covered=decimal.Decimal("1.0"),
                         missing_lines=0,
                         excluded_lines=0,
-                        num_branches=0 if has_branches else None,
-                        num_partial_branches=0 if has_branches else None,
-                        covered_branches=0 if has_branches else None,
-                        missing_branches=0 if has_branches else None,
+                        num_branches=0,
+                        num_partial_branches=0,
+                        covered_branches=0,
+                        missing_branches=0,
                     ),
                 )
             if set(line.split()) & {
@@ -340,7 +340,6 @@ def _(code: str, has_branches: bool = True) -> coverage_module.Coverage:
                 coverage_obj.files[current_file].excluded_lines.append(line_number)
                 coverage_obj.files[current_file].info.excluded_lines += 1
                 coverage_obj.info.excluded_lines += 1
-
             if has_branches and "branch" in line:
                 coverage_obj.files[current_file].info.num_branches += 1
                 coverage_obj.info.num_branches += 1
@@ -353,21 +352,22 @@ def _(code: str, has_branches: bool = True) -> coverage_module.Coverage:
                 elif "branch missing" in line:
                     coverage_obj.files[current_file].info.missing_branches += 1
                     coverage_obj.info.missing_branches += 1
-
             info = coverage_obj.files[current_file].info
             coverage_obj.files[
                 current_file
             ].info.percent_covered = coverage_module.compute_coverage(
                 num_covered=info.covered_lines,
                 num_total=info.num_statements,
+                num_branches_covered=info.covered_branches,
+                num_branches_total=info.num_branches,
             )
-
             info = coverage_obj.info
             coverage_obj.info.percent_covered = coverage_module.compute_coverage(
                 num_covered=info.covered_lines,
                 num_total=info.num_statements,
+                num_branches_covered=info.covered_branches,
+                num_branches_total=info.num_branches,
             )
-
         return coverage_obj
 
     return _
@@ -446,7 +446,7 @@ def coverage_json():
                 "summary": {
                     "covered_lines": 6,
                     "num_statements": 10,
-                    "percent_covered": 60.0,
+                    "percent_covered": 53.84615384615384615384615385,
                     "missing_lines": 4,
                     "excluded_lines": 0,
                     "num_branches": 3,
@@ -461,7 +461,7 @@ def coverage_json():
         "totals": {
             "covered_lines": 6,
             "num_statements": 10,
-            "percent_covered": 60.0,
+            "percent_covered": 53.84615384615384615384615385,
             "missing_lines": 4,
             "excluded_lines": 0,
             "num_branches": 3,

tests/unit/test_coverage.py

@@ -39,6 +39,24 @@ def test_compute_coverage(num_covered, num_total, expected_coverage):
     )
 
 
+@pytest.mark.parametrize(
+    "num_covered, num_total, branch_covered, branch_total, expected_coverage",
+    [
+        (0, 10, 0, 15, "0"),
+        (0, 0, 0, 0, "1"),
+        (5, 0, 5, 0, "1"),
+        (5, 10, 5, 10, "0.5"),
+        (1, 50, 1, 50, "0.02"),
+    ],
+)
+def test_compute_coverage_with_branches(
+    num_covered, num_total, branch_covered, branch_total, expected_coverage
+):
+    assert coverage.compute_coverage(
+        num_covered, num_total, branch_covered, branch_total
+    ) == decimal.Decimal(expected_coverage)
+
+
 def test_get_coverage_info(mocker, coverage_json, coverage_obj):
     run = mocker.patch(
         "coverage_comment.subprocess.run", return_value=json.dumps(coverage_json)

tests/unit/test_template.py

@@ -44,7 +44,7 @@ def test_get_comment_markdown(coverage_obj, diff_coverage_obj):
         .split(maxsplit=4)
     )
 
-    expected = ["92%", "60%", "50%", "bar", "<!-- foo -->"]
+    expected = ["92%", "53.84%", "50%", "bar", "<!-- foo -->"]
 
     assert result == expected
 
@@ -79,17 +79,17 @@ def test_template(coverage_obj, diff_coverage_obj):
     expected = """## Coverage report (foo)
 
 
-<img title="Coverage for the whole project went from 92% to 60%" src="https://img.shields.io/badge/Coverage%20evolution-92%25%20%3E%2060%25-red.svg"> <img title="50% of the statement lines added by this PR are covered" src="https://img.shields.io/badge/PR%20Coverage-50%25-orange.svg"><details><summary>Click to see where and how coverage changed</summary><table><thead>
+<img title="Coverage for the whole project went from 92% to 53.84%" src="https://img.shields.io/badge/Coverage%20evolution-92%25%20%3E%2053%25-red.svg"> <img title="50% of the statement lines added by this PR are covered" src="https://img.shields.io/badge/PR%20Coverage-50%25-orange.svg"><details><summary>Click to see where and how coverage changed</summary><table><thead>
   <tr><th>File</th><th>Statements</th><th>Missing</th><th>Coverage</th><th>Coverage<br>(new stmts)</th><th>Lines missing</th></tr>
 </thead>
 <tbody><tr>
 <td colspan="6">&nbsp;&nbsp;<b>codebase</b></td><tr>
 <td>&nbsp;&nbsp;<a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3">code.py</a></td>
-<td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="This PR adds 10 statements to codebase/code.py. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/10-%28%2B10%29-007ec6.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="This PR adds 4 statements missing coverage to codebase/code.py. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/4-%28%2B4%29-red.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="The coverage rate of codebase/code.py is 60% (6/10). The file did not seem to exist on the base branch." src="https://img.shields.io/badge/60%25-%286/10%29-orange.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="In this PR, 4 new statements are added to codebase/code.py, 2 of which are covered (50%)." src="https://img.shields.io/badge/50%25-%282/4%29-orange.svg"></a></td><td><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3R6-R8">6-8</a></td></tbody>
+<td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="This PR adds 10 statements to codebase/code.py. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/10-%28%2B10%29-007ec6.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="This PR adds 4 statements missing coverage to codebase/code.py. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/4-%28%2B4%29-red.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="The coverage rate of codebase/code.py is 53.84% (6/10). The file did not seem to exist on the base branch." src="https://img.shields.io/badge/53%25-%286/10%29-orange.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3"><img title="In this PR, 4 new statements are added to codebase/code.py, 2 of which are covered (50%)." src="https://img.shields.io/badge/50%25-%282/4%29-orange.svg"></a></td><td><a href="https://github.com/org/repo/pull/5/files#diff-c05d5557f0c1ff3761df2f49e3b541cfc161f4f0d63e2a66d568f090065bc3d3R6-R8">6-8</a></td></tbody>
 <tfoot>
 <tr>
 <td><b>Project Total</b></td>
-<td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="This PR adds 10 statements to the whole project. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/10-%28%2B10%29-007ec6.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="This PR adds 4 statements missing coverage to the whole project. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/4-%28%2B4%29-red.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="The coverage rate of the whole project is 60% (6/10). The file did not seem to exist on the base branch." src="https://img.shields.io/badge/60%25-%286/10%29-orange.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="In this PR, 4 new statements are added to the whole project, 2 of which are covered (50%)." src="https://img.shields.io/badge/50%25-%282/4%29-orange.svg"></a></td><td>&nbsp;</td>
+<td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="This PR adds 10 statements to the whole project. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/10-%28%2B10%29-007ec6.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="This PR adds 4 statements missing coverage to the whole project. The file did not seem to exist on the base branch." src="https://img.shields.io/badge/4-%28%2B4%29-red.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="The coverage rate of the whole project is 53.84% (6/10). The file did not seem to exist on the base branch." src="https://img.shields.io/badge/53%25-%286/10%29-orange.svg"></a></td><td align="center"><a href="https://github.com/org/repo/pull/5/files#diff-4b0bf2efa3367c0072ac2bf1e234e703dc46b47aaa4fe9d3b01737b1a15752b1"><img title="In this PR, 4 new statements are added to the whole project, 2 of which are covered (50%)." src="https://img.shields.io/badge/50%25-%282/4%29-orange.svg"></a></td><td>&nbsp;</td>
 </tr>
 </tfoot>
 </table>