Refactor file path formatting

Moved the `replace` file function to a util so that
it can be used in spec files.

Also wrote some specs to test that new util function.

app/assets/javascripts/pipelines/stores/test_reports/getters.js

-import { addIconStatus, formattedTime } from './utils';
+import { addIconStatus, formatFilePath, formattedTime } from './utils';
 
 export const getTestSuites = (state) => {
   const { test_suites: testSuites = [] } = state.testReports;
@@ -20,13 +20,7 @@ export const getSuiteTests = (state) => {
   return testCases
     .map((testCase) => ({
       ...testCase,
-      /**
-       * filePath is the file string appended onto the blob path.
-       * We need to make sure the file string doesn't start with `./` when appending.
-       * Even though we could leave the `/` at the beginning, we can't guarantee that the
-       * file string will have `/` at the beginning so we should just remove it and add it manually
-       */
-      filePath: testCase.file ? `${state.blobPath}/${testCase.file.replace(/^\.?\//, '')}` : null,
+      filePath: testCase.file ? `${state.blobPath}/${formatFilePath(testCase.file)}` : null,
     }))
     .map(addIconStatus)
     .slice(start, start + perPage);

app/assets/javascripts/pipelines/stores/test_reports/utils.js

 import { __, sprintf } from '../../../locale';
 import { TestStatus } from '../../constants';
 
+/**
+ * Removes `./` from the beginning of a file path so it can be appended onto a blob path
+ * @param {String} file
+ * @returns {String}  - formatted value
+ */
+export function formatFilePath(file) {
+  return file.replace(/^\.?\/*/, '');
+}
+
 export function iconForTestStatus(status) {
   switch (status) {
     case TestStatus.SUCCESS:

spec/frontend/pipelines/test_reports/stores/getters_spec.js

 import { getJSONFixture } from 'helpers/fixtures';
 import * as getters from '~/pipelines/stores/test_reports/getters';
-import { iconForTestStatus, formattedTime } from '~/pipelines/stores/test_reports/utils';
+import {
+  iconForTestStatus,
+  formatFilePath,
+  formattedTime,
+} from '~/pipelines/stores/test_reports/utils';
 
 describe('Getters TestReports Store', () => {
   let state;
@@ -76,7 +80,7 @@ describe('Getters TestReports Store', () => {
       const expected = testReports.test_suites[0].test_cases
         .map((x) => ({
           ...x,
-          filePath: `${state.blobPath}/${x.file.replace(/^\.?\//, '')}`,
+          filePath: `${state.blobPath}/${formatFilePath(x.file)}`,
           formattedTime: formattedTime(x.execution_time),
           icon: iconForTestStatus(x.status),
         }))

spec/frontend/pipelines/test_reports/stores/utils_spec.js

-import { formattedTime } from '~/pipelines/stores/test_reports/utils';
+import { formatFilePath, formattedTime } from '~/pipelines/stores/test_reports/utils';
 
 describe('Test reports utils', () => {
+  describe('formatFilePath', () => {
+    describe('when file string starts with "./"', () => {
+      it('should return the file string without the beginning "./"', () => {
+        const result = formatFilePath('./test.js');
+
+        expect(result).toBe('test.js');
+      });
+    });
+
+    describe('when file string starts with "/"', () => {
+      it('should return the file string without the beginning "/"', () => {
+        const result = formatFilePath('/test.js');
+
+        expect(result).toBe('test.js');
+      });
+    });
+
+    describe('when file string starts with more than one "/"', () => {
+      it('should return the file string without any of the beginning "/"', () => {
+        const result = formatFilePath('.//////////////test.js');
+
+        expect(result).toBe('test.js');
+      });
+    });
+
+    describe('when file string starts without either "." or "/"', () => {
+      it('should return the file string without change', () => {
+        const result = formatFilePath('test.js');
+
+        expect(result).toBe('test.js');
+      });
+    });
+
+    describe('when file string contains but does not start with "./"', () => {
+      it('should return the file string without change', () => {
+        const result = formatFilePath('mock/path./test.js');
+
+        expect(result).toBe('mock/path./test.js');
+      });
+    });
+  });
+
   describe('formattedTime', () => {
     describe('when time is smaller than a second', () => {
       it('should return time in milliseconds fixed to 2 decimals', () => {

spec/frontend/pipelines/test_reports/test_suite_table_spec.js

@@ -4,6 +4,7 @@ import { GlButton, GlFriendlyWrap, GlLink, GlPagination } from '@gitlab/ui';
 import { getJSONFixture } from 'helpers/fixtures';
 import SuiteTable from '~/pipelines/components/test_reports/test_suite_table.vue';
 import * as getters from '~/pipelines/stores/test_reports/getters';
+import { formatFilePath } from '~/pipelines/stores/test_reports/utils';
 import { TestStatus } from '~/pipelines/constants';
 import skippedTestCases from './mock_data';
 
@@ -85,8 +86,7 @@ describe('Test reports suite table', () => {
 
     it('renders the file name for the test with a copy button', () => {
       const { file } = testCases[0];
-      // remove `./` from the beginning of the file path
-      const relativeFile = file.replace(/^\.?\//, '');
+      const relativeFile = formatFilePath(file);
       const filePath = `${blobPath}/${relativeFile}`;
       const row = findCaseRowAtIndex(0);
       const fileLink = findLinkForRow(row);