Add comprehensive tests for parseConfiguration function, handle non-object parser results consistently (fixes #1523).

test/parse-configuration-test.mjs

@@ -13,12 +13,94 @@ const testObject = {
 };
 const successfulTestObjectResult = {
   "config": testObject,
-  "message": ""
+  "message": null
+};
+const successfulParser = () => testObject;
+const failingParser = () => {
+  throw new Error("failingParser");
 };
-const testObjectJsonString = JSON.stringify(testObject);
 
-test("json object, default parsers", (t) => {
+test("json object, default parser", (t) => {
   t.plan(1);
-  const actual = parseConfiguration("name", testObjectJsonString);
+  const actual = parseConfiguration("name", JSON.stringify(testObject));
   t.deepEqual(actual, successfulTestObjectResult);
 });
+
+test("invalid json, default parser", (t) => {
+  t.plan(1);
+  const actual = parseConfiguration("name", "{");
+  const expected = {
+    "config": null,
+    "message": "Unable to parse 'name'; Parser 0: Expected property name or '}' in JSON at position 1 (line 1 column 2)"
+  };
+  t.deepEqual(actual, expected);
+});
+
+test("parser gets passed content", (t) => {
+  t.plan(2);
+  const content = "content";
+  const parser = (text) => {
+    t.is(text, content);
+    return {};
+  };
+  const actual = parseConfiguration("name", content, [ parser ]);
+  const expected = {
+    "config": {},
+    "message": null
+  };
+  t.deepEqual(actual, expected);
+});
+
+test("parser returns undefined/null/number/string/array", (t) => {
+  t.plan(5);
+  const expected = {
+    "config": {},
+    "message": null
+  };
+  const testCases = [ undefined, null, 10, "string", [] ];
+  for (const testCase of testCases) {
+    /** @type {import("../lib/markdownlint.mjs").ConfigurationParser} */
+    const parser =
+      // @ts-ignore
+      () => testCase;
+    const actual = parseConfiguration("name", "content", [ parser ]);
+    t.deepEqual(actual, expected);
+  }
+});
+
+test("custom parsers, successful/failing", (t) => {
+  t.plan(1);
+  const actual = parseConfiguration("name", "", [ successfulParser, failingParser ]);
+  t.deepEqual(actual, successfulTestObjectResult);
+});
+
+test("custom parsers, failing/successful", (t) => {
+  t.plan(1);
+  const actual = parseConfiguration("name", "", [ failingParser, successfulParser ]);
+  t.deepEqual(actual, successfulTestObjectResult);
+});
+
+test("custom parsers, failing/successful(undefined)", (t) => {
+  t.plan(1);
+  const actual = parseConfiguration(
+    "name",
+    "",
+    // @ts-ignore
+    [ failingParser, () => undefined ]
+  );
+  const expected = {
+    "config": {},
+    "message": null
+  };
+  t.deepEqual(actual, expected);
+});
+
+test("custom parsers, failing/failing", (t) => {
+  t.plan(1);
+  const actual = parseConfiguration("name", "", [ failingParser, failingParser ]);
+  const expected = {
+    "config": null,
+    "message": "Unable to parse 'name'; Parser 0: failingParser; Parser 1: failingParser"
+  };
+  t.deepEqual(actual, expected);
+});