Add unit tests for TOML placeholder parsing

pyproject.toml

@@ -74,6 +74,7 @@ test = [
     "pyright==1.1.361",
     "pytest~=7.4",
     "pytest-dependency~=0.5",
+    "pytest-describe~=2.2",
     "syrupy~=4.6",
     "copier_template_tester",
     "pyyaml-include<2", # https://github.com/copier-org/copier/issues/1568

src/hexdoc/utils/deserialize/toml.py

@@ -31,6 +31,7 @@
 
 
 def fill_placeholders(data: TOMLDict):
+    """Replaces hexdoc-style string placeholders in-place in a parsed TOML file."""
     _fill_placeholders(data, [data], set())
 
 

test/utils/deserialize/test_toml.py

@@ -0,0 +1,183 @@
+# pyright: reportUnusedFunction=none
+
+import copy
+
+import pytest
+from hexdoc.utils.deserialize.toml import TOMLDict, fill_placeholders
+
+
+def _fill_placeholders_assert_valid(data: TOMLDict, want: TOMLDict):
+    got = copy.deepcopy(data)
+    fill_placeholders(got)
+    assert got == want
+
+
+def describe_fill_placeholders():
+    def describe_valid_input():
+        @pytest.mark.parametrize(
+            ["data", "want"],
+            [
+                [{}, {}],
+                [{"": ""}, {"": ""}],
+                [{"key": "value"}, {"key": "value"}],
+            ],
+        )
+        def no_placeholders(data: TOMLDict, want: TOMLDict):
+            _fill_placeholders_assert_valid(data, want)
+
+        @pytest.mark.parametrize(
+            ["data", "want"],
+            [
+                [
+                    {"key": "{var}", "var": "value"},
+                    {"key": "value", "var": "value"},
+                ],
+                [
+                    {"key": "foo {var} bar", "var": "value"},
+                    {"key": "foo value bar", "var": "value"},
+                ],
+                [
+                    {"key": "foo {var} bar {var}", "var": "value"},
+                    {"key": "foo value bar value", "var": "value"},
+                ],
+            ],
+        )
+        def simple_placeholders(data: TOMLDict, want: TOMLDict):
+            _fill_placeholders_assert_valid(data, want)
+
+        @pytest.mark.parametrize(
+            ["data", "want"],
+            [
+                [
+                    {"foo": {"key": "{^var}"}, "var": "value"},
+                    {"foo": {"key": "value"}, "var": "value"},
+                ],
+                [
+                    {"foo": {"bar": {"key": "{^^var}"}}, "var": "value"},
+                    {"foo": {"bar": {"key": "value"}}, "var": "value"},
+                ],
+                [
+                    {"foo": {"bar": {"baz": {"key": "{^^^var}"}}}, "var": "value"},
+                    {"foo": {"bar": {"baz": {"key": "value"}}}, "var": "value"},
+                ],
+            ],
+        )
+        def parent_references(data: TOMLDict, want: TOMLDict):
+            _fill_placeholders_assert_valid(data, want)
+
+        @pytest.mark.parametrize(
+            ["data", "want"],
+            [
+                [
+                    {"key": "{$var}", "var": "value"},
+                    {"key": "value", "var": "value"},
+                ],
+                [
+                    {"foo": {"key": "{$var}"}, "var": "value"},
+                    {"foo": {"key": "value"}, "var": "value"},
+                ],
+                [
+                    {"foo": {"bar": {"key": "{$var}"}}, "var": "value"},
+                    {"foo": {"bar": {"key": "value"}}, "var": "value"},
+                ],
+                [
+                    {"foo": {"bar": {"baz": {"key": "{$var}"}}}, "var": "value"},
+                    {"foo": {"bar": {"baz": {"key": "value"}}}, "var": "value"},
+                ],
+            ],
+        )
+        def root_references(data: TOMLDict, want: TOMLDict):
+            _fill_placeholders_assert_valid(data, want)
+
+        @pytest.mark.parametrize(
+            ["data", "want"],
+            [
+                [
+                    {"foo": ["{var}"], "var": "value"},
+                    {"foo": ["value"], "var": "value"},
+                ],
+                [
+                    {"foo": [{"key": "{^var}"}], "var": "value"},
+                    {"foo": [{"key": "value"}], "var": "value"},
+                ],
+                [
+                    {"foo": ["{$var}"], "var": "value"},
+                    {"foo": ["value"], "var": "value"},
+                ],
+                [
+                    {"foo": [{"key": "{$var}"}], "var": "value"},
+                    {"foo": [{"key": "value"}], "var": "value"},
+                ],
+            ],
+        )
+        def arrays(data: TOMLDict, want: TOMLDict):
+            _fill_placeholders_assert_valid(data, want)
+
+        def describe_intrinsic_functions():
+            @pytest.mark.parametrize(
+                ["data", "want"],
+                [
+                    [
+                        {"key": {"!Raw": ""}},
+                        {"key": ""},
+                    ],
+                    [
+                        {"key": {"!Raw": "value"}},
+                        {"key": "value"},
+                    ],
+                    [
+                        {"key": {"!Raw": "{var}"}, "var": "value"},
+                        {"key": "{var}", "var": "value"},
+                    ],
+                    [
+                        {"key": {"!Raw": "^{.+}$"}},
+                        {"key": "^{.+}$"},
+                    ],
+                    [
+                        {"key": {"!Raw": {}}},
+                        {"key": {}},
+                    ],
+                    [
+                        {"key": {"!Raw": {"!Raw": "value"}}},
+                        {"key": {"!Raw": "value"}},
+                    ],
+                ],
+            )
+            def raw(data: TOMLDict, want: TOMLDict):
+                _fill_placeholders_assert_valid(data, want)
+
+            @pytest.mark.parametrize(
+                ["data", "want"],
+                [
+                    [
+                        {"key": {"!None": ""}},
+                        {"key": None},
+                    ],
+                    [
+                        {"key": {"!None": "value"}},
+                        {"key": None},
+                    ],
+                    [
+                        {"key": {"!None": {}}},
+                        {"key": None},
+                    ],
+                ],
+            )
+            def none(data: TOMLDict, want: TOMLDict):
+                _fill_placeholders_assert_valid(data, want)
+
+    @pytest.mark.parametrize(
+        ["data", "want_err"],
+        [
+            [{"key": "{var}"}, KeyError],
+            pytest.param(
+                {"key": "{^var}", "var": "value"},
+                KeyError,
+                marks=pytest.mark.xfail,
+            ),
+            [{"key": "{var}", "var": 0}, TypeError],
+        ],
+    )
+    def invalid_input(data: TOMLDict, want_err: type[Exception]):
+        with pytest.raises(want_err):
+            fill_placeholders(data)