Add tests for helpers readSettings

src/helpers.ts

@@ -27,18 +27,17 @@ export function readSettings<T>(serviceName: string, settingsFileName: string):
     throw new Error(`[${serviceName}] Unable to load configuration file ${settingsFileName}.`);
   }
 
-  let parseErrors: JSONC.ParseError[];
+  const parseErrors: JSONC.ParseError[] = [];
 
   const settings = JSONC.parse(rawConfig, parseErrors) as T;
 
   // This extra level of validation really shouldn't be necessary since the
   // file passed schema validation. Still, better safe than crashing.
   if (parseErrors && parseErrors.length > 0) {
-    throw new Error(
-      `[${serviceName}] Unable to load configuration file: ${parseErrors
-        .map(error => log.error("${serviceName}", `${error?.error}`))
-        .join("\n")}`,
-    );
+    const parseErrorsAsString = parseErrors.map(parseError => JSON.stringify(parseError)).join(" ");
+    log.error(serviceName, parseErrorsAsString);
+    const errorMessage = `[${serviceName}] Unable to load configuration file: ${parseErrorsAsString}`;
+    throw new Error(errorMessage);
   }
 
   return settings;

tests/helpers.test.ts

@@ -0,0 +1,116 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Neil Enns. All rights reserved.
+ *  Licensed under the MIT License. See LICENSE in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+import {closeSync, existsSync, openSync, unlinkSync, writeFileSync} from 'fs';
+import * as JSONC from "jsonc-parser";
+import * as helpers from "./../src/helpers";
+
+describe("helpers", () => {
+  const settingsFilePath = `${__dirname}/settings.json`;
+
+  beforeEach(() => {
+    closeSync(openSync(settingsFilePath, 'w'));
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+    if (existsSync(settingsFilePath)) {
+      unlinkSync(settingsFilePath);
+    }
+  });
+
+   test("Verify can load settings.json", () => {
+     const serviceName = "Settings";
+     const expectedSettings = {"foo": "bar"};
+     writeFileSync(settingsFilePath, JSON.stringify(expectedSettings));
+
+     const actualSettings = helpers.readSettings(serviceName, settingsFilePath);
+
+     expect(actualSettings).toEqual(expectedSettings);
+   });
+
+   test("Verify cannot load settings.json because it does not exist", () => {
+     //eslint-disable-next-line no-console
+     console.log = jest.fn();
+     const serviceName = "Settings";
+     unlinkSync(settingsFilePath);
+
+     const actualSettings = helpers.readSettings(serviceName, settingsFilePath);
+
+     //eslint-disable-next-line no-console
+     expect(console.log).toHaveBeenCalledWith(expect.stringContaining("[Settings] Unable to read the configuration file: ENOENT: no such file or directory"));
+     expect(actualSettings).toBeNull();
+   });
+
+   test("Verify throws if rawConfig empty", () => {
+     const serviceName = "Settings";
+     const expectedSettings = "";
+     writeFileSync(settingsFilePath, expectedSettings);
+
+     expect(() => {helpers.readSettings(serviceName, settingsFilePath)}).toThrow(Error);
+   });
+
+   test("Verify throws with message if rawConfig empty", () => {
+     const serviceName = "Settings";
+     const expectedSettings = "";
+     writeFileSync(settingsFilePath, expectedSettings);
+
+     try {
+       helpers.readSettings(serviceName, settingsFilePath);
+     } catch (error) {
+       expect(error.message).toBe(`[${serviceName}] Unable to load configuration file ${settingsFilePath}.`);
+     }
+   });
+
+  test("Verify throws if json invalid", () => {
+    const serviceName = "Settings";
+    const expectedSettings = {};
+    writeFileSync(settingsFilePath, JSON.stringify(expectedSettings));
+    const mockAddListener = jest.spyOn(JSONC, 'parse');
+    mockAddListener.mockImplementation((rawConfig, parseErrors) => {
+        parseErrors.push({
+            error: 1,
+            offset: 2,
+            length: 3,
+        });
+        return {};
+    });
+
+    expect(() => {helpers.readSettings(serviceName, settingsFilePath)}).toThrow(Error);
+  });
+
+  test("Verify throws with message if json invalid", () => {
+    const serviceName = "Settings";
+    const expectedSettings = {};
+    writeFileSync(settingsFilePath, JSON.stringify(expectedSettings));
+    const mockAddListener = jest.spyOn(JSONC, 'parse');
+    const parseError1 = {
+      error: 1,
+      offset: 2,
+      length: 3,
+    };
+    const parseError2 = {
+      error: 3,
+      offset: 2,
+      length: 1,
+    };
+    mockAddListener.mockImplementation((rawConfig, parseErrors) => {
+        parseErrors.push(parseError1);
+        parseErrors.push(parseError2);
+        return {};
+    });
+    //eslint-disable-next-line no-console
+    console.log = jest.fn();
+
+     try {
+       helpers.readSettings(serviceName, settingsFilePath);
+     } catch (error) {
+       const parseErrorsAsString = `${JSON.stringify(parseError1)} ${JSON.stringify(parseError2)}`;
+       //eslint-disable-next-line no-console
+       expect(console.log).toHaveBeenCalledWith(expect.stringContaining(`[${serviceName}] ${parseErrorsAsString}`));
+       expect(error.message).toBe(`[${serviceName}] Unable to load configuration file: ${parseErrorsAsString}`);
+     }
+  });
+});
+