usethis-python · nathanjmcdougall · Jan 18, 2025 · Jan 18, 2025 · Jan 18, 2025 · Jan 18, 2025
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', 'coverage' to the 'test' dependency group in 'pyproject.toml'.
+✔ Adding dependencies 'pytest', 'pytest-cov' to the 'test' dependency group in 'pyproject.toml'.
 ✔ Adding pytest config to 'pyproject.toml'.
 ✔ Enabling Ruff rule 'PT' in 'pyproject.toml'.
 ✔ Creating '/tests'.

diff --git a/src/usethis/_core/tool.py b/src/usethis/_core/tool.py
@@ -25,6 +25,7 @@
 from usethis._integrations.uv.init import ensure_pyproject_toml
 from usethis._tool import (
     ALL_TOOLS,
+    CoverageTool,
     DeptryTool,
     PreCommitTool,
     PyprojectFmtTool,
@@ -34,6 +35,33 @@
 )
 
 
+def use_coverage(*, remove: bool = False) -> None:
+    tool = CoverageTool()
+
+    ensure_pyproject_toml()
+
+    if not remove:
+        add_deps_to_group(tool.dev_deps, "test")
+
+        tool.add_pyproject_configs()
+
+        if PytestTool().is_used():
+            _coverage_instructions_pytest()
+        else:
+            _coverage_instructions_basic()
+    else:
+        tool.remove_pyproject_configs()
+        remove_deps_from_group(tool.dev_deps, "test")
+
+
+def _coverage_instructions_basic() -> None:
+    box_print("Run 'coverage help' to see available coverage commands.")
+
+
+def _coverage_instructions_pytest() -> None:
+    box_print("Run 'pytest --cov' to run your tests with coverage.")
+
+
 def use_deptry(*, remove: bool = False) -> None:
     tool = DeptryTool()
 
@@ -53,6 +81,7 @@ def use_deptry(*, remove: bool = False) -> None:
 
 def use_pre_commit(*, remove: bool = False) -> None:
     tool = PreCommitTool()
+    pyproject_fmt_tool = PyprojectFmtTool()
 
     ensure_pyproject_toml()
 
@@ -62,13 +91,14 @@ def use_pre_commit(*, remove: bool = False) -> None:
             if _tool.is_used():
                 _tool.add_pre_commit_repo_configs()
 
-        if PyprojectFmtTool().is_used():
+        if pyproject_fmt_tool.is_used():
             # We will use pre-commit instead of the dev-dep.
-            remove_deps_from_group(PyprojectFmtTool().get_unique_dev_deps(), "dev")
-            use_pyproject_fmt()
+            remove_deps_from_group(pyproject_fmt_tool.get_unique_dev_deps(), "dev")
+            pyproject_fmt_tool.add_pyproject_configs()
+            _pyproject_fmt_instructions_pre_commit()
 
         if RequirementsTxtTool().is_used():
-            use_requirements_txt()
+            _requirements_txt_instructions_pre_commit()
 
         if not get_hook_names():
             add_placeholder_hook()
@@ -91,12 +121,15 @@ def use_pre_commit(*, remove: bool = False) -> None:
         remove_deps_from_group(tool.dev_deps, "dev")
 
         # Need to add a new way of running some hooks manually if they are not dev
-        # dependencies yet
-        if PyprojectFmtTool().is_used():
-            use_pyproject_fmt()
+        # dependencies yet - explain to the user.
+        if pyproject_fmt_tool.is_used():
+            add_deps_to_group(pyproject_fmt_tool.dev_deps, "dev")
+            _pyproject_fmt_instructions_basic()
 
+        # Likewise, explain how to manually generate the requirements.txt file, since
+        # they're not going to do it via pre-commit anymore.
         if RequirementsTxtTool().is_used():
-            use_requirements_txt()
+            _requirements_txt_instructions_basic()
 
 
 def use_pyproject_fmt(*, remove: bool = False) -> None:
@@ -115,18 +148,24 @@ def use_pyproject_fmt(*, remove: bool = False) -> None:
         tool.add_pyproject_configs()
 
         if not is_pre_commit:
-            box_print("Run 'pyproject-fmt pyproject.toml' to run pyproject-fmt.")
+            _pyproject_fmt_instructions_basic()
         else:
-            box_print(
-                "Run 'pre-commit run pyproject-fmt --all-files' to run pyproject-fmt."
-            )
+            _pyproject_fmt_instructions_pre_commit()
     else:
         tool.remove_pyproject_configs()
         if PreCommitTool().is_used():
             tool.remove_pre_commit_repo_configs()
         remove_deps_from_group(tool.dev_deps, "dev")
 
 
+def _pyproject_fmt_instructions_basic() -> None:
+    box_print("Run 'pyproject-fmt pyproject.toml' to run pyproject-fmt.")
+
+
+def _pyproject_fmt_instructions_pre_commit() -> None:
+    box_print("Run 'pre-commit run pyproject-fmt --all-files' to run pyproject-fmt.")
+
+
 def use_pytest(*, remove: bool = False) -> None:
     tool = PytestTool()
 
@@ -137,6 +176,7 @@ def use_pytest(*, remove: bool = False) -> None:
         tool.add_pyproject_configs()
         if RuffTool().is_used():
             select_ruff_rules(tool.get_associated_ruff_rules())
+
         # deptry currently can't scan the tests folder for dev deps
         # https://github.com/fpgmaas/deptry/issues/302
         add_pytest_dir()
@@ -149,6 +189,9 @@ def use_pytest(*, remove: bool = False) -> None:
         )
         box_print("Add test functions with the format 'test_*()'.")
         box_print("Run 'pytest' to run the tests.")
+
+        if CoverageTool().is_used():
+            _coverage_instructions_pytest()
     else:
         if is_bitbucket_used():
             remove_bitbucket_pytest_steps()
@@ -159,6 +202,9 @@ def use_pytest(*, remove: bool = False) -> None:
         remove_deps_from_group(tool.dev_deps, "test")
         remove_pytest_dir()  # Last, since this is a manual step
 
+        if CoverageTool().is_used():
+            _coverage_instructions_basic()
+
 
 def use_requirements_txt(*, remove: bool = False) -> None:
     tool = RequirementsTxtTool()
@@ -190,11 +236,9 @@ def use_requirements_txt(*, remove: bool = False) -> None:
             )
 
         if not is_pre_commit:
-            box_print(
-                "Run 'uv export --no-dev --output-file=requirements.txt' to write 'requirements.txt'."
-            )
+            _requirements_txt_instructions_basic()
         else:
-            box_print("Run the 'pre-commit run uv-export' to write 'requirements.txt'.")
+            _requirements_txt_instructions_pre_commit()
     else:
         if PreCommitTool().is_used():
             tool.remove_pre_commit_repo_configs()
@@ -204,6 +248,16 @@ def use_requirements_txt(*, remove: bool = False) -> None:
             path.unlink()
 
 
+def _requirements_txt_instructions_basic() -> None:
+    box_print(
+        "Run 'uv export --no-dev --output-file=requirements.txt' to write 'requirements.txt'."
+    )
+
+
+def _requirements_txt_instructions_pre_commit() -> None:
+    box_print("Run the 'pre-commit run uv-export' to write 'requirements.txt'.")
+
+
 def use_ruff(*, remove: bool = False) -> None:
     tool = RuffTool()
 

diff --git a/src/usethis/_integrations/pyproject/io.py b/src/usethis/_integrations/pyproject/io.py
@@ -1,4 +1,5 @@
 import tomllib
+from functools import cache
 from pathlib import Path
 from typing import Any
 
@@ -11,8 +12,13 @@
 
 
 def read_pyproject_toml() -> tomlkit.TOMLDocument:
+    return read_pyproject_toml_from_path(Path.cwd() / "pyproject.toml")
+
+
+@cache
+def read_pyproject_toml_from_path(path: Path) -> tomlkit.TOMLDocument:
     try:
-        return tomlkit.parse((Path.cwd() / "pyproject.toml").read_text())
+        return tomlkit.parse(path.read_text())
     except FileNotFoundError:
         msg = "'pyproject.toml' not found in the current directory."
         raise PyProjectTOMLNotFoundError(msg)
@@ -33,4 +39,5 @@ def read_pyproject_dict() -> dict[str, Any]:
 
 
 def write_pyproject_toml(toml_document: tomlkit.TOMLDocument) -> None:
+    read_pyproject_toml_from_path.cache_clear()
     (Path.cwd() / "pyproject.toml").write_text(tomlkit.dumps(toml_document))
diff --git a/src/usethis/_integrations/uv/call.py b/src/usethis/_integrations/uv/call.py
@@ -1,3 +1,4 @@
+from usethis._integrations.pyproject.io import read_pyproject_toml_from_path
 from usethis._integrations.uv.errors import UVSubprocessFailedError
 from usethis._subprocess import SubprocessFailedError, call_subprocess
 
@@ -8,6 +9,7 @@ def call_uv_subprocess(args: list[str]) -> str:
     Raises:
         UVSubprocessFailedError: If the subprocess fails.
     """
+    read_pyproject_toml_from_path.cache_clear()
     try:
         return call_subprocess(["uv", *args])
     except SubprocessFailedError as err:

diff --git a/src/usethis/_interface/tool.py b/src/usethis/_interface/tool.py
@@ -6,6 +6,7 @@
 from usethis._config import offline_opt, quiet_opt, usethis_config
 from usethis._console import err_print
 from usethis._core.tool import (
+    use_coverage,
     use_deptry,
     use_pre_commit,
     use_pyproject_fmt,
@@ -22,6 +23,14 @@
 )
 
 
+@app.command(help="Use the coverage code coverage measurement tool.")
+def coverage(
+    remove: bool = remove_opt, offline: bool = offline_opt, quiet: bool = quiet_opt
+) -> None:
+    with usethis_config.set(offline=offline, quiet=quiet):
+        _run_tool(use_coverage, remove=remove)
+
+
 @app.command(
     help="Use the deptry linter: avoid missing or superfluous dependency declarations."
 )

diff --git a/src/usethis/_tool.py b/src/usethis/_tool.py
@@ -161,6 +161,46 @@ def remove_pyproject_configs(self) -> None:
                     first_removal = False
 
 
+class CoverageTool(Tool):
+    @property
+    def name(self) -> str:
+        return "coverage"
+
+    @property
+    def dev_deps(self) -> list[str]:
+        return ["coverage[toml]"]
+
+    def get_pyproject_configs(self) -> list[PyProjectConfig]:
+        return [
+            PyProjectConfig(
+                id_keys=["tool", "coverage", "run"],
+                value={
+                    "source": ["src"],
+                    "omit": ["*/pytest-of-*/*"],
+                },
+            ),
+            PyProjectConfig(
+                id_keys=["tool", "coverage", "report"],
+                value={
+                    "exclude_also": [
+                        "if TYPE_CHECKING:",
+                        "raise AssertionError",
+                        "raise NotImplementedError",
+                        "assert_never(.*)",
+                        "class .*\\bProtocol\\):",
+                        "@(abc\\.)?abstractmethod",
+                    ]
+                },
+            ),
+        ]
+
+    def get_pyproject_id_keys(self):
+        return [["tool", "coverage"]]
+
+    def get_managed_files(self):
+        return [Path(".coveragerc")]
+
+
 class DeptryTool(Tool):
     @property
     def name(self) -> str:
@@ -238,7 +278,7 @@ def name(self) -> str:
 
     @property
     def dev_deps(self) -> list[str]:
-        return ["pytest", "pytest-cov", "coverage[toml]"]
+        return ["pytest", "pytest-cov"]
 
     def get_pyproject_configs(self) -> list[PyProjectConfig]:
         return [
@@ -254,26 +294,6 @@ def get_pyproject_configs(self) -> list[PyProjectConfig]:
                     }
                 },
             ),
-            PyProjectConfig(
-                id_keys=["tool", "coverage", "run"],
-                value={
-                    "source": ["src"],
-                    "omit": ["*/pytest-of-*/*"],
-                },
-            ),
-            PyProjectConfig(
-                id_keys=["tool", "coverage", "report"],
-                value={
-                    "exclude_also": [
-                        "if TYPE_CHECKING:",
-                        "raise AssertionError",
-                        "raise NotImplementedError",
-                        "assert_never(.*)",
-                        "class .*\\bProtocol\\):",
-                        "@(abc\\.)?abstractmethod",
-                    ]
-                },
-            ),
         ]
 
     def get_associated_ruff_rules(self) -> list[str]:
@@ -385,6 +405,7 @@ def get_managed_files(self):
 
 
 ALL_TOOLS: list[Tool] = [
+    CoverageTool(),
     DeptryTool(),
     PreCommitTool(),
     PyprojectFmtTool(),