Add an acceptance test for --force-filetype

tests/acceptance/test_nonjson_instance_files.py

@@ -0,0 +1,60 @@
+import json
+
+import pytest
+
+from check_jsonschema.parsers.json5 import ENABLED as JSON5_ENABLED
+
+SIMPLE_SCHEMA = {
+    "$schema": "http://json-schema.org/draft-07/schema",
+    "properties": {
+        "title": {"type": "string"},
+    },
+    "additionalProperties": False,
+}
+PASSING_DOCUMENT = """
+// a comment
+{"title": "doc one"}
+"""
+FAILING_DOCUMENT = """
+// a comment
+{"title": 2}
+"""
+
+
+@pytest.mark.skipif(not JSON5_ENABLED, reason="test requires json5")
+@pytest.mark.parametrize("passing_data", [True, False])
+def test_json5_filetype_forced_on_json_suffixed_instance(
+    run_line, tmp_path, passing_data
+):
+    schemafile = tmp_path / "schema.json"
+    schemafile.write_text(json.dumps(SIMPLE_SCHEMA))
+
+    doc = tmp_path / "doc.json"
+    if passing_data:
+        doc.write_text(PASSING_DOCUMENT)
+    else:
+        doc.write_text(FAILING_DOCUMENT)
+
+    result = run_line(
+        [
+            "check-jsonschema",
+            "--force-filetype",
+            "json5",
+            "--schemafile",
+            str(schemafile),
+            str(doc),
+        ]
+    )
+    assert result.exit_code == (0 if passing_data else 1)
+
+    # but even in the passing case, a rerun without the force flag will fail
+    if passing_data:
+        result_without_filetype = run_line(
+            [
+                "check-jsonschema",
+                "--schemafile",
+                str(schemafile),
+                str(doc),
+            ]
+        )
+        assert result_without_filetype.exit_code == 1