test: add tests for cmd.run and cmd.run_interactive

Author: PhilipNelson5

tests/test_cmd.py

@@ -55,3 +55,78 @@ def decode(self, encoding="utf-8", errors="strict"):
 
     with pytest.raises(CharacterSetDecodeError):
         cmd._try_decode(_bytes())
+
+
+class TestRun:
+    def test_stdout_captured(self):
+        result = cmd.run("python -c \"print('hello')\"")
+        assert "hello" in result.out
+        assert isinstance(result.stdout, bytes)
+        assert b"hello" in result.stdout
+
+    def test_stderr_captured(self):
+        result = cmd.run("python -c \"import sys; print('err msg', file=sys.stderr)\"")
+        assert "err msg" in result.err
+        assert isinstance(result.stderr, bytes)
+        assert b"err msg" in result.stderr
+
+    def test_zero_return_code_on_success(self):
+        result = cmd.run('python -c "import sys; sys.exit(0)"')
+        assert result.return_code == 0
+
+    def test_nonzero_return_code_on_failure(self):
+        result = cmd.run('python -c "import sys; sys.exit(42)"')
+        assert result.return_code == 42
+
+    def test_env_passed_to_subprocess(self):
+        result = cmd.run(
+            "python -c \"import os; print(os.environ['CZ_TEST_VAR'])\"",
+            env={"CZ_TEST_VAR": "sentinelvalue"},
+        )
+        assert "sentinelvalue" in result.out
+        assert result.return_code == 0
+
+    def test_env_merged_with_os_environ(self, monkeypatch):
+        monkeypatch.setenv("CZ_EXISTING_VAR", "fromenv")
+        result = cmd.run(
+            "python -c \"import os; print(os.environ['CZ_EXISTING_VAR'])\"",
+            env={"CZ_EXTRA_VAR": "extra"},
+        )
+        assert "fromenv" in result.out
+
+    def test_empty_stdout_and_stderr(self):
+        result = cmd.run('python -c "pass"')
+        assert result.out == ""
+        assert result.err == ""
+        assert result.stdout == b""
+        assert result.stderr == b""
+
+    def test_no_env_uses_os_environ(self, monkeypatch):
+        monkeypatch.setenv("CZ_NO_ENV_TEST", "inherited")
+        result = cmd.run("python -c \"import os; print(os.environ['CZ_NO_ENV_TEST'])\"")
+        assert "inherited" in result.out
+
+
+class TestRunInteractive:
+    def test_zero_return_code_on_success(self):
+        return_code = cmd.run_interactive('python -c "import sys; sys.exit(0)"')
+        assert return_code == 0
+
+    def test_nonzero_return_code_on_failure(self):
+        return_code = cmd.run_interactive('python -c "import sys; sys.exit(3)"')
+        assert return_code == 3
+
+    def test_env_passed_to_subprocess(self):
+        return_code = cmd.run_interactive(
+            "python -c \"import os, sys; sys.exit(0 if os.environ['CZ_ITEST_VAR'] == 'val' else 1)\"",
+            env={"CZ_ITEST_VAR": "val"},
+        )
+        assert return_code == 0
+
+    def test_env_merged_with_os_environ(self, monkeypatch):
+        monkeypatch.setenv("CZ_ITEST_EXISTING", "yes")
+        return_code = cmd.run_interactive(
+            "python -c \"import os, sys; sys.exit(0 if os.environ['CZ_ITEST_EXISTING'] == 'yes' else 1)\"",
+            env={"CZ_ITEST_EXTRA": "extra"},
+        )
+        assert return_code == 0