fix: cleaner error when formatter is missing. new test for same.

lib/package/bundleLinter.js

@@ -1,5 +1,5 @@
 /*
-  Copyright 2019-2022 Google LLC
+  Copyright 2019-2022,2024 Google LLC
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -170,8 +170,10 @@ var getFormatter = function (format) {
     try {
       return require(formatterPath);
     } catch (ex) {
-      ex.message = `There was a problem loading formatter: ${formatterPath}\nError: ${ex.message}`;
-      throw ex;
+      throw new Error(
+        `There was a problem loading formatter: ${formatterPath}`,
+        { cause: ex }
+      );
     }
   } else {
     return null;

test/specs/testFormatters.js

@@ -1,5 +1,5 @@
 /*
-  Copyright 2019-2021 Google LLC
+  Copyright 2019-2021,2024 Google LLC
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -17,10 +17,8 @@
 /* jslint esversion:9 */
 
 const assert = require("assert"),
-      debug = require("debug")("apigeelint:Formatters"),
-      //Bundle = require("../../lib/package/Bundle.js"),
-      //util = require("util"),
-      bl = require("../../lib/package/bundleLinter.js");
+  debug = require("debug")("apigeelint:Formatters"),
+  bl = require("../../lib/package/bundleLinter.js");
 
 const formatters = [
   "checkstyle.js",
@@ -38,18 +36,53 @@ const formatters = [
   "pdf.js"
 ];
 
-describe("Formatters", function() {
-  configuration.source.path = './test/fixtures/resources/sample-proxy-with-issues/response-shaping/apiproxy';
-  configuration.output = () => {}; // suppress output
+function randomString(L) {
+  L = L || 18;
+  let s = "";
+  do {
+    s += Math.random().toString(36).substring(2, 15);
+  } while (s.length < L);
+  return s.substring(0, L);
+}
+
+describe("Formatters", function () {
+  let capturedOutput = null;
+  configuration.source.path =
+    "./test/fixtures/resources/sample-proxy-with-issues/response-shaping/apiproxy";
+  configuration.output = (formatted) => {
+    capturedOutput = formatted;
+  };
   debug("test configuration: " + JSON.stringify(configuration));
 
-  formatters.forEach( formatter => {
-    it(`Linting with formatter ${formatter} should succeed`, function() {
-      configuration.formatter = formatter;
-      let bundle = bl.lint(configuration);
-      let report = bundle.getReport();
-      assert.ok(report);
-      debug("formatted report: \n" + report);
+  formatters.forEach((formatter) => {
+    it(`Formatter ${formatter} should succeed`, function () {
+      try {
+        capturedOutput = null;
+        configuration.formatter = formatter;
+        const bundle = bl.lint(configuration);
+        const report = bundle.getReport();
+        assert.ok(report);
+        assert.ok(capturedOutput);
+        //console.log(capturedOutput);
+        debug("formatted report: \n" + capturedOutput);
+      } catch (e) {
+        assert.fail("formatter implementation throws exception: " + e.stack);
+      }
     });
   });
+
+  const nonExistingFormatterName = `${randomString(9)}.js`;
+  it(`Non-existing Formatter ${nonExistingFormatterName} should fail`, function () {
+    try {
+      configuration.formatter = nonExistingFormatterName;
+      const _bundle = bl.lint(configuration);
+      assert.fail("formatter implementation succeeds unexpectedly.");
+    } catch (e) {
+      assert.ok(e);
+      assert.equal(
+        e.message,
+        `There was a problem loading formatter: ./third_party/formatters/${nonExistingFormatterName}`
+      );
+    }
+  });
 });