tests: Add basic test runner using pytest.

.gitignore

@@ -1 +1,3 @@
 *~
+.pytest_cache
+__pycache__

README.md

@@ -127,6 +127,7 @@ Optional:
 
 * python-keyring is required for the `keyring` transform to pull passwords from
   kwallet/gnome-keyring/etc.
+* pytest to run unit tests (only needed if you develop and submit patches).
 
 ## Limitations
 

tests/data/basics.expected.ini

@@ -0,0 +1,28 @@
+line_both = True
+line_sys_ignored=False
+
+line_src=True
+[section-both]
+line_both = True
+line_both_ignored = False
+line_sys_ignored = False
+line_formatting_mismatch_1=123
+line_formatting_mismatch_2 = 123
+
+line_formatting_nospaces_src=123
+line_src = True
+[section-both-ignored]
+line_both = True
+
+
+[section-sys]
+line_sys_ignored = False
+
+[section-sys-ignored]
+line_sys = True
+line_sys_ignored = False
+
+[section][weird-kde-style]
+something = Yes really
+[section-src]
+line_src = True

tests/data/basics.json

@@ -0,0 +1,7 @@
+{
+  "args": [
+    "-is", "section-sys-ignored",
+    "-is", "section-src-ignored",
+    "-ikr", ".*", ".*_ignored$"
+  ]
+}

tests/data/basics.src.ini

@@ -0,0 +1,26 @@
+line_both = True
+line_src=True
+line_src_ignored=False
+
+[section-both]
+line_both = True
+line_both_ignored = True
+line_src = True
+line_src_ignored = False
+line_formatting_nospaces_src=123
+line_formatting_mismatch_1=123
+line_formatting_mismatch_2 = 123
+
+[section-both-ignored]
+line_both = True
+
+[section-src]
+line_src = True
+line_src_ignored = False
+
+[section-src-ignored]
+line_src = True
+line_src_ignored = False
+
+[section][weird-kde-style]
+something = Yes really

tests/data/basics.sys.ini

@@ -0,0 +1,29 @@
+line_both = True
+line_sys=True
+line_sys_ignored=False
+
+[section-both]
+line_both = False
+line_both_ignored = False
+line_sys = True
+line_sys_ignored = False
+line_formatting_nospaces_sys=123
+line_formatting_mismatch_1 = 123
+line_formatting_mismatch_2=123
+
+[section-both-ignored]
+line_both = False
+
+[section-sys1]
+line_sys = True
+
+[section-sys]
+line_sys = True
+line_sys_ignored = False
+
+[section-sys-ignored]
+line_sys = True
+line_sys_ignored = False
+
+[section][weird-kde-style]
+something = Yes really

tests/test_runner.py

@@ -0,0 +1,34 @@
+import json
+from pathlib import Path
+import pytest
+import subprocess
+
+_TESTS_DIR = Path(__file__).parent
+_DATA_DIR = _TESTS_DIR / "data"
+_CHEZMOI_INI_MANAGER = _TESTS_DIR.parent / "bin" / "chezmoi_ini_manager.py"
+
+# Discover tests
+_TESTS = [e.stem for e in _DATA_DIR.glob("*.json")]
+
+
+@pytest.mark.parametrize("name", _TESTS)
+def test_example(name: str):
+    base_name = _DATA_DIR / name
+    with base_name.with_suffix(".json").open(mode="rt") as f:
+        options = json.load(f)
+    with base_name.with_suffix(".sys.ini").open(mode="rb") as sys_file:
+
+        result = subprocess.run(
+            [_CHEZMOI_INI_MANAGER, "-s", base_name.with_suffix(".src.ini")]
+            + options["args"],
+            stdin=sys_file,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
+    assert result.returncode == options.get("expected_retcode", 0)
+    assert result.stderr.decode("utf-8", errors="strict") == options.get(
+        "expected_stderr", ""
+    )
+    with base_name.with_suffix(".expected.ini").open(mode="rb") as expected_file:
+        expected_data = expected_file.read()
+        assert expected_data.split(b"\n") == result.stdout.split(b"\n")