Only add pytest-cov when both coverage and pytest are used (#235)

nathanjmcdougall · web-flow · commit 61fc24c7df67 · 2025-01-24T11:27:45.000+13:00
diff --git a/README.md b/README.md
@@ -73,7 +73,7 @@ To use pytest, run:
 
 ```console
 $ uvx usethis tool pytest
-✔ Adding dependencies 'pytest', 'pytest-cov' to the 'test' dependency group in 'pyproject.toml'.
+✔ Adding dependency 'pytest' to the 'test' dependency group in 'pyproject.toml'.
 ✔ Adding pytest config to 'pyproject.toml'.
 ✔ Enabling Ruff rule 'PT' in 'pyproject.toml'.
 ✔ Creating '/tests'.
@@ -107,16 +107,13 @@ Add a new tool to a Python project, including:
 
 Currently supported tools:
 
-- `usethis tool ruff`
-- `usethis tool pytest`
+- `usethis tool coverage`
 - `usethis tool deptry`
 - `usethis tool pre-commit`
 - `usethis tool pyproject-fmt`
+- `usethis tool pytest`
 - `usethis tool requirements.txt`
-
-Example:
-
-`usethis tool ruff`
+- `usethis tool ruff`
 
 Supported arguments:
 
diff --git a/src/usethis/_core/tool.py b/src/usethis/_core/tool.py
@@ -21,7 +21,11 @@
     select_ruff_rules,
 )
 from usethis._integrations.uv.call import call_uv_subprocess
-from usethis._integrations.uv.deps import add_deps_to_group, remove_deps_from_group
+from usethis._integrations.uv.deps import (
+    Dependency,
+    add_deps_to_group,
+    remove_deps_from_group,
+)
 from usethis._integrations.uv.init import ensure_pyproject_toml
 from usethis._tool import (
     ALL_TOOLS,
@@ -41,7 +45,10 @@ def use_coverage(*, remove: bool = False) -> None:
     ensure_pyproject_toml()
 
     if not remove:
-        add_deps_to_group(tool.dev_deps, "test")
+        deps = tool.dev_deps
+        if PytestTool().is_used():
+            deps += [Dependency(name="pytest-cov")]
+        add_deps_to_group(deps, "test")
 
         tool.add_pyproject_configs()
 
@@ -51,7 +58,7 @@ def use_coverage(*, remove: bool = False) -> None:
             _coverage_instructions_basic()
     else:
         tool.remove_pyproject_configs()
-        remove_deps_from_group(tool.dev_deps, "test")
+        remove_deps_from_group([*tool.dev_deps, Dependency(name="pytest-cov")], "test")
 
 
 def _coverage_instructions_basic() -> None:
@@ -172,7 +179,11 @@ def use_pytest(*, remove: bool = False) -> None:
     ensure_pyproject_toml()
 
     if not remove:
-        add_deps_to_group(tool.dev_deps, "test")
+        deps = tool.dev_deps
+        if CoverageTool().is_used():
+            deps += [Dependency(name="pytest-cov")]
+        add_deps_to_group(deps, "test")
+
         tool.add_pyproject_configs()
         if RuffTool().is_used():
             select_ruff_rules(tool.get_associated_ruff_rules())
@@ -199,7 +210,8 @@ def use_pytest(*, remove: bool = False) -> None:
         if RuffTool().is_used():
             deselect_ruff_rules(tool.get_associated_ruff_rules())
         tool.remove_pyproject_configs()
-        remove_deps_from_group(tool.dev_deps, "test")
+        remove_deps_from_group([*tool.dev_deps, Dependency(name="pytest-cov")], "test")
+
         remove_pytest_dir()  # Last, since this is a manual step
 
         if CoverageTool().is_used():
diff --git a/src/usethis/_tool.py b/src/usethis/_tool.py
@@ -42,6 +42,18 @@ def dev_deps(self) -> list[Dependency]:
         """The tool's development dependencies."""
         return []
 
+    def get_extra_dev_deps(self) -> list[Dependency]:
+        """Additional development dependencies for the tool.
+
+        These won't be installed automatically - usually they are only needed for
+        integrations with other tools and will only be conditionally installed.
+
+        However, they will be used to determine if the tool is being used, so they
+        should be considered characteristic of the tool. It follows that they should be
+        removed when the tool is being removed.
+        """
+        return []
+
     def get_pre_commit_repos(self) -> list[LocalRepo | UriRepo]:
         """Get the pre-commit repository configurations for the tool."""
         return []
@@ -70,15 +82,20 @@ def is_used(self) -> bool:
         2. Whether any of the tool's managed files are in the project.
         3. Whether any of the tool's managed pyproject.toml sections are present.
         """
-        is_any_deps = any(is_dep_in_any_group(dep) for dep in self.dev_deps)
-        is_any_files = any(
-            file.exists() and file.is_file() for file in self.get_managed_files()
-        )
-        is_any_pyproject = any(
-            do_id_keys_exist(id_keys) for id_keys in self.get_pyproject_id_keys()
-        )
-
-        return is_any_deps or is_any_files or is_any_pyproject
+        for file in self.get_managed_files():
+            if file.exists() and file.is_file():
+                return True
+        for id_keys in self.get_pyproject_id_keys():
+            if do_id_keys_exist(id_keys):
+                return True
+        for dep in self.dev_deps:
+            if is_dep_in_any_group(dep):
+                return True
+        for extra_dep in self.get_extra_dev_deps():
+            if is_dep_in_any_group(extra_dep):
+                return True
+
+        return False
 
     def add_pre_commit_repo_configs(self) -> None:
         """Add the tool's pre-commit configuration."""
@@ -272,10 +289,10 @@ def name(self) -> str:
 
     @property
     def dev_deps(self) -> list[Dependency]:
-        return [
-            Dependency(name="pytest"),
-            Dependency(name="pytest-cov"),
-        ]
+        return [Dependency(name="pytest")]
+
+    def get_extra_dev_deps(self) -> list[Dependency]:
+        return [Dependency(name="pytest-cov")]
 
     def get_pyproject_configs(self) -> list[PyProjectConfig]:
         return [
diff --git a/tests/usethis/_core/test_tool.py b/tests/usethis/_core/test_tool.py
@@ -88,7 +88,7 @@ def test_no_pyproject_toml(
                 )
 
         @pytest.mark.usefixtures("_vary_network_conn")
-        def test_pytest_used(
+        def test_pytest_integration(
             self, uv_init_dir: Path, capfd: pytest.CaptureFixture[str]
         ):
             with change_cwd(uv_init_dir):
@@ -106,7 +106,7 @@ def test_pytest_used(
                 out, err = capfd.readouterr()
                 assert not err
                 assert out == (
-                    "✔ Adding dependency 'coverage' to the 'test' group in 'pyproject.toml'.\n"
+                    "✔ Adding dependencies 'coverage', 'pytest-cov' to the 'test' group in \n'pyproject.toml'.\n"
                     "✔ Adding coverage config to 'pyproject.toml'.\n"
                     "☐ Run 'pytest --cov' to run your tests with coverage.\n"
                 )
@@ -141,6 +141,27 @@ def test_roundtrip(self, uv_init_dir: Path, capfd: pytest.CaptureFixture[str]):
                 "✔ Removing dependency 'coverage' from the 'test' group in 'pyproject.toml'.\n"
             )
 
+        def test_pytest_integration(
+            self, uv_init_dir: Path, capfd: pytest.CaptureFixture[str]
+        ):
+            with change_cwd(uv_init_dir):
+                # Arrange
+                with usethis_config.set(quiet=True):
+                    use_pytest()
+                    use_coverage()
+
+                # Act
+                use_coverage(remove=True)
+
+                # Assert
+                assert get_deps_from_group("test") == [Dependency(name="pytest")]
+                out, err = capfd.readouterr()
+                assert not err
+                assert out == (
+                    "✔ Removing coverage config from 'pyproject.toml'.\n"
+                    "✔ Removing dependencies 'coverage', 'pytest-cov' from the 'test' group in \n'pyproject.toml'.\n"
+                )
+
 
 class TestDeptry:
     class TestAdd:
@@ -810,13 +831,14 @@ def test_no_pyproject(self, tmp_path: Path, capfd: pytest.CaptureFixture[str]):
                 assert is_dep_satisfied_in(
                     Dependency(name="pytest"), in_=list(deps_from_test)
                 )
-                assert is_dep_satisfied_in(
+                # pytest-cov should only be added when we are using coverage
+                assert not is_dep_satisfied_in(
                     Dependency(name="pytest-cov"), in_=list(deps_from_test)
                 )
                 out, _ = capfd.readouterr()
                 assert out == (
                     "✔ Writing 'pyproject.toml'.\n"
-                    "✔ Adding dependencies 'pytest', 'pytest-cov' to the 'test' group in \n'pyproject.toml'.\n"
+                    "✔ Adding dependency 'pytest' to the 'test' group in 'pyproject.toml'.\n"
                     "✔ Adding pytest config to 'pyproject.toml'.\n"
                     "✔ Creating '/tests'.\n"
                     "✔ Writing '/tests/conftest.py'.\n"
@@ -838,7 +860,7 @@ def test_bitbucket_integration(self, uv_init_dir: Path):
             assert "pytest" in (uv_init_dir / "bitbucket-pipelines.yml").read_text()
 
         @pytest.mark.usefixtures("_vary_network_conn")
-        def test_coverage_notice(
+        def test_coverage_integration(
             self, uv_init_dir: Path, capfd: pytest.CaptureFixture[str]
         ):
             with change_cwd(uv_init_dir):
@@ -968,7 +990,7 @@ def test_remove(self, uv_init_dir: Path, capfd: pytest.CaptureFixture[str]):
                     "✔ Removing 'Test on 3.12' from default pipeline in 'bitbucket-pipelines.yml'.\n"
                     "✔ Adding cache 'uv' definition to 'bitbucket-pipelines.yml'.\n"
                     "✔ Removing pytest config from 'pyproject.toml'.\n"
-                    "✔ Removing dependencies 'pytest', 'pytest-cov' from the 'test' group in 'pyproject.toml'.\n"
+                    "✔ Removing dependency 'pytest' from the 'test' group in 'pyproject.toml'.\n"
                     "✔ Removing '/tests'.\n"
                 ).replace("\n", "").replace(" ", "")
                 contents = (uv_init_dir / "bitbucket-pipelines.yml").read_text()
@@ -997,6 +1019,27 @@ def test_remove(self, uv_init_dir: Path, capfd: pytest.CaptureFixture[str]):
 """
                 )
 
+        def test_coverage_integration(
+            self, uv_init_dir: Path, capfd: pytest.CaptureFixture[str]
+        ):
+            with change_cwd(uv_init_dir):
+                # Arrange
+                with usethis_config.set(quiet=True):
+                    use_coverage()
+                    use_pytest()
+
+                # Act
+                use_pytest(remove=True)
+
+            # Assert
+            out, _ = capfd.readouterr()
+            assert out == (
+                "✔ Removing pytest config from 'pyproject.toml'.\n"
+                "✔ Removing dependencies 'pytest', 'pytest-cov' from the 'test' group in \n'pyproject.toml'.\n"
+                "✔ Removing '/tests'.\n"
+                "☐ Run 'coverage help' to see available coverage commands.\n"
+            )
+
 
 class TestRuff:
     class TestAdd:
diff --git a/tests/usethis/test_tool.py b/tests/usethis/test_tool.py
@@ -40,6 +40,9 @@ def dev_deps(self) -> list[Dependency]:
             Dependency(name="flake8"),
         ]
 
+    def get_extra_dev_deps(self) -> list[Dependency]:
+        return [Dependency(name="pytest")]
+
     def get_pre_commit_repos(self) -> list[LocalRepo | UriRepo]:
         return [
             UriRepo(
@@ -221,6 +224,42 @@ def test_empty(self, uv_init_dir: Path):
             # Assert
             assert not result
 
+        def test_extra_dev_deps(self, uv_init_dir: Path):
+            # Arrange
+            tool = MyTool()
+
+            with change_cwd(uv_init_dir):
+                add_deps_to_group(
+                    [
+                        Dependency(name="pytest"),
+                    ],
+                    "test",
+                )
+
+                # Act
+                result = tool.is_used()
+
+            # Assert
+            assert result
+
+        def test_not_extra_dev_deps(self, uv_init_dir: Path):
+            # Arrange
+            tool = MyTool()
+
+            with change_cwd(uv_init_dir):
+                add_deps_to_group(
+                    [
+                        Dependency(name="isort"),
+                    ],
+                    "test",
+                )
+
+                # Act
+                result = tool.is_used()
+
+            # Assert
+            assert not result
+
     class TestAddPreCommitRepoConfigs:
         def test_no_repo_configs(self, uv_init_dir: Path):
             # Arrange
