From e46caae881ed1a30f8ed2dede823c876f4b4403e Mon Sep 17 00:00:00 2001
From: Huafu Gandon <huafu.gandon@gmail.com>
Date: Thu, 19 Jul 2018 15:33:33 +0200
Subject: [PATCH] fix: big refactor + fixes (mainly cache key + coverage)

---
 index.d.ts                                    | 11 ----
 index.js                                      | 15 ------
 package.json                                  | 12 ++---
 preprocessor.js                               |  1 -
 scripts/tests.js                              | 10 ----
 src/index.ts                                  | 35 +++++++++++++
 src/postprocess.ts                            | 35 +++++++------
 src/{preprocessor.ts => preprocess.ts}        | 43 +++-------------
 src/transpile-if-ts.ts                        | 23 ---------
 src/transpiler.ts                             |  5 +-
 src/{jest-types.ts => types.ts}               | 38 ++++++--------
 src/utils/constants.ts                        | 12 +++++
 src/utils/get-babel-rc.ts                     | 50 +++++++++++++++++++
 src/utils/get-cache-key.ts                    | 31 ++++++++++++
 src/{utils.ts => utils/index.ts}              | 14 +++---
 src/{ => utils}/logger.ts                     |  0
 tests/__tests__/get-cache-key.spec.ts         | 11 ++--
 tests/__tests__/transpiler.spec.ts            | 21 ++++++--
 tests/coverage-simple/.gitignore              |  1 +
 tests/coverage-simple/Hello.ts                | 28 +++++++++++
 tests/coverage-simple/NullCoverage.js         |  6 +++
 tests/coverage-simple/__tests__/Hello.test.ts |  9 ++++
 tests/coverage-simple/package.json            | 22 ++++++++
 tests/coverage-simple/tsconfig.json           | 10 ++++
 tests/coverage-simple/yarn.lock               |  4 ++
 tsconfig.build.json                           | 11 ++++
 tsconfig.json                                 |  7 +--
 27 files changed, 299 insertions(+), 166 deletions(-)
 delete mode 100644 index.d.ts
 delete mode 100644 index.js
 delete mode 100644 preprocessor.js
 create mode 100644 src/index.ts
 rename src/{preprocessor.ts => preprocess.ts} (65%)
 delete mode 100644 src/transpile-if-ts.ts
 rename src/{jest-types.ts => types.ts} (65%)
 create mode 100644 src/utils/constants.ts
 create mode 100644 src/utils/get-babel-rc.ts
 create mode 100644 src/utils/get-cache-key.ts
 rename src/{utils.ts => utils/index.ts} (94%)
 rename src/{ => utils}/logger.ts (100%)
 create mode 100644 tests/coverage-simple/.gitignore
 create mode 100644 tests/coverage-simple/Hello.ts
 create mode 100644 tests/coverage-simple/NullCoverage.js
 create mode 100644 tests/coverage-simple/__tests__/Hello.test.ts
 create mode 100644 tests/coverage-simple/package.json
 create mode 100644 tests/coverage-simple/tsconfig.json
 create mode 100644 tests/coverage-simple/yarn.lock
 create mode 100644 tsconfig.build.json

diff --git a/index.d.ts b/index.d.ts
deleted file mode 100644
index 206d91423f..0000000000
--- a/index.d.ts
+++ /dev/null
@@ -1,11 +0,0 @@
-import * as _install from './install';
-import * as preprocessor from './preprocessor';
-
-interface TsJestModule {
-  install: typeof _install.install;
-  process: typeof preprocessor.process;
-  getCacheKey: typeof preprocessor.getCacheKey;
-}
-
-declare const tsJestModule: TsJestModule;
-export = tsJestModule;
diff --git a/index.js b/index.js
deleted file mode 100644
index 13ad594168..0000000000
--- a/index.js
+++ /dev/null
@@ -1,15 +0,0 @@
-// Avoid require()'ing the preprocessor when index.js gets loaded as part
-// of the transpiled test file output, to avoid tripping this bug in
-// babel-core: https://github.com/babel/babel/pull/6524 which is to be
-// fixed in babel-core 7.0.
-// Related ts-jest issue: https://github.com/kulshekhar/ts-jest/issues/367
-function lazyRequire(fnName) {
-  return function() {
-    return require('./dist/preprocessor')[fnName].apply(null, arguments);
-  };
-}
-
-module.exports = {
-  getCacheKey: lazyRequire('getCacheKey'),
-  process: lazyRequire('process'),
-};
diff --git a/package.json b/package.json
index a6abcd5519..501a3327ef 100644
--- a/package.json
+++ b/package.json
@@ -1,18 +1,18 @@
 {
   "name": "ts-jest",
   "version": "23.0.1",
-  "main": "index.js",
+  "main": "dist/index.js",
   "types": "./dist/index.d.ts",
   "description": "A preprocessor with sourcemap support to help use Typescript with Jest",
   "scripts": {
-    "build": "cpx index.d.ts dist/ && tsc -p .",
-    "build:watch": "cpx index.d.ts dist/ && tsc -p . -w",
+    "build": "tsc -p tsconfig.build.json",
+    "build:watch": "tsc -p tsconfig.build.json -w",
     "test:nolint": "npm run clean-build && node scripts/tests.js",
-    "clean": "rimraf dist/**/* && rimraf tests/simple/coverage && rimraf tests/simple-async/coverage && rimraf tests/**/*/debug.txt && rimraf tests/**/node_modules",
+    "clean": "rimraf dist/**/* && rimraf tests/*/coverage && rimraf tests/*/debug.txt && rimraf tests/*/node_modules",
     "clean-build": "npm run clean && npm run build",
     "pretest": "npm run tslint && npm run clean-build",
     "test": "node scripts/tests.js",
-    "tslint": "tslint src/*.ts",
+    "tslint": "tslint src/**/*.ts",
     "doc": "doctoc .",
     "prepublish": "npm run clean-build",
     "precommit": "lint-staged",
@@ -38,7 +38,7 @@
   "homepage": "https://github.com/kulshekhar/ts-jest#readme",
   "jest": {
     "transform": {
-      "^.+\\.tsx?$": "<rootDir>/dist/preprocessor.js"
+      "^.+\\.tsx?$": "<rootDir>/dist/index.js"
     },
     "testRegex": "tests/__tests__/.*\\.spec\\.ts$",
     "testPathIgnorePatterns": [
diff --git a/preprocessor.js b/preprocessor.js
deleted file mode 100644
index d56eb74241..0000000000
--- a/preprocessor.js
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = require('./dist/preprocessor');
\ No newline at end of file
diff --git a/scripts/tests.js b/scripts/tests.js
index 3baec1dd28..36934fae5d 100644
--- a/scripts/tests.js
+++ b/scripts/tests.js
@@ -25,16 +25,6 @@ function createIntegrationMock() {
     const rootDir = path.resolve('.');
     const testCaseModuleFolder = path.join(testCaseNodeModules, 'ts-jest');
 
-    // Copy javascript files
-    fs.copySync(
-      path.resolve(rootDir, 'index.js'),
-      path.resolve(testCaseModuleFolder, 'index.js')
-    );
-    fs.copySync(
-      path.resolve(rootDir, 'preprocessor.js'),
-      path.resolve(testCaseModuleFolder, 'preprocessor.js')
-    );
-
     // Copy package.json
     fs.copySync(
       path.resolve(rootDir, 'package.json'),
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000000..c49fd4fb34
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,35 @@
+// structure of this file heavilly inspired on:
+// https://github.com/facebook/jest/blob/master/packages/babel-jest/src/index.js
+
+import jestPreset from 'babel-preset-jest';
+import getCacheKeyForArgs from './utils/get-cache-key';
+import { TsJestContext, JestCacheKeyArguments } from './types';
+import preprocess from './preprocess';
+
+const createTransformer = (options?: any): jest.Transformer => {
+  const cache = Object.create(null);
+
+  options = Object.assign({}, options, {
+    compact: false,
+    plugins: (options && options.plugins) || [],
+    presets: ((options && options.presets) || []).concat([jestPreset]),
+    sourceMaps: 'both',
+  });
+  delete options.cacheDirectory;
+  delete options.filename;
+
+  const context: TsJestContext = { cache, options };
+
+  const getCacheKey = (...args: any[]) =>
+    getCacheKeyForArgs(args as JestCacheKeyArguments, context);
+
+  return {
+    canInstrument: true,
+    getCacheKey,
+    process: preprocess,
+    createTransformer: undefined as any,
+  };
+};
+
+export default createTransformer();
+export { createTransformer };
diff --git a/src/postprocess.ts b/src/postprocess.ts
index b86e72d6cb..f91876d3ab 100644
--- a/src/postprocess.ts
+++ b/src/postprocess.ts
@@ -16,26 +16,24 @@ function importBabelDeps() {
   istanbulPlugin = require('babel-plugin-istanbul').default;
   jestPreset = require('babel-preset-jest');
 }
-import { CompilerOptions } from 'typescript/lib/typescript';
+import { CompilerOptions } from 'typescript';
 import {
   BabelTransformOptions,
-  CodeSourceMapPair,
-  JestConfig,
   PostProcessHook,
-  TransformOptions,
+  JestCacheKeyOptions,
   TsJestConfig,
-} from './jest-types';
-import { logOnce } from './logger';
+} from './types';
+import { logOnce } from './utils/logger';
 
 // Function that takes the transpiled typescript and runs it through babel/whatever.
 export function postProcessCode(
   compilerOptions: CompilerOptions,
-  jestConfig: JestConfig,
+  jestConfig: jest.ProjectConfig,
   tsJestConfig: TsJestConfig,
-  transformOptions: TransformOptions,
-  transpileOutput: CodeSourceMapPair,
+  transformOptions: jest.TransformOptions,
+  transpileOutput: jest.TransformedSource,
   filePath: string,
-): CodeSourceMapPair {
+): jest.TransformedSource {
   const postHook = getPostProcessHook(
     compilerOptions,
     jestConfig,
@@ -58,11 +56,11 @@ function createBabelTransformer(
   delete options.filename;
 
   return (
-    codeSourcemapPair: CodeSourceMapPair,
+    codeSourcemapPair: jest.TransformedSource,
     filename: string,
-    config: JestConfig,
-    transformOptions: TransformOptions,
-  ): CodeSourceMapPair => {
+    config: jest.ProjectConfig,
+    transformOptions: JestCacheKeyOptions,
+  ): jest.TransformedSource => {
     const theseOptions = Object.assign(
       { filename, inputSourceMap: codeSourcemapPair.map },
       options,
@@ -81,17 +79,18 @@ function createBabelTransformer(
         ],
       ]);
     }
-    // Babel has incorrect typings, where the map is an object instead of a string. So we have to typecast it here
-    return (babel.transform(
+
+    // we typecast here because babel returns a more complete object than the one expected by jest
+    return babel.transform(
       codeSourcemapPair.code,
       theseOptions,
-    ) as any) as CodeSourceMapPair;
+    ) as jest.TransformedSource;
   };
 }
 
 export const getPostProcessHook = (
   tsCompilerOptions: CompilerOptions,
-  jestConfig: JestConfig,
+  jestConfig: jest.ProjectConfig,
   tsJestConfig: TsJestConfig,
 ): PostProcessHook => {
   if (tsJestConfig.skipBabel) {
diff --git a/src/preprocessor.ts b/src/preprocess.ts
similarity index 65%
rename from src/preprocessor.ts
rename to src/preprocess.ts
index a5a04e8ad5..748a2aca82 100644
--- a/src/preprocessor.ts
+++ b/src/preprocess.ts
@@ -1,22 +1,14 @@
-import * as crypto from 'crypto';
-import {
-  BabelTransformOptions,
-  CodeSourceMapPair,
-  JestConfig,
-  Path,
-  TransformOptions,
-} from './jest-types';
-import { flushLogs, logOnce } from './logger';
+import { flushLogs, logOnce } from './utils/logger';
 import { postProcessCode } from './postprocess';
 import { getTSConfig, getTSJestConfig, runTsDiagnostics } from './utils';
 import { transpileTypescript } from './transpiler';
 
-export function process(
+export default function preprocess(
   src: string,
-  filePath: Path,
-  jestConfig: JestConfig,
-  transformOptions: TransformOptions = { instrument: false },
-): CodeSourceMapPair | string {
+  filePath: jest.Path,
+  jestConfig: jest.ProjectConfig,
+  transformOptions: jest.TransformOptions,
+): jest.TransformedSource | string {
   // transformOptions.instrument is a proxy for collectCoverage
   // https://github.com/kulshekhar/ts-jest/issues/201#issuecomment-300572902
   const compilerOptions = getTSConfig(jestConfig.globals, jestConfig.rootDir);
@@ -28,7 +20,7 @@ export function process(
   const isHtmlFile = /\.html$/.test(filePath);
 
   // This is to support angular 2. See https://github.com/kulshekhar/ts-jest/pull/145
-  if (isHtmlFile && jestConfig.globals.__TRANSFORM_HTML__) {
+  if (isHtmlFile && (jestConfig.globals as any).__TRANSFORM_HTML__) {
     src = 'module.exports=' + JSON.stringify(src) + ';';
   }
 
@@ -76,24 +68,3 @@ export function process(
 
   return { code: outputText.code, map: outputText.map };
 }
-
-/**
- * This is the function Jest uses to check if it has the file already in cache
- */
-export function getCacheKey(
-  fileData: string,
-  filePath: Path,
-  jestConfigStr: string,
-  transformOptions: TransformOptions = { instrument: false },
-): string {
-  const jestConfig: JestConfig = JSON.parse(jestConfigStr);
-
-  const tsConfig = getTSConfig(jestConfig.globals, jestConfig.rootDir);
-
-  return crypto
-    .createHash('md5')
-    .update(JSON.stringify(tsConfig), 'utf8')
-    .update(JSON.stringify(transformOptions), 'utf8')
-    .update(fileData + filePath + jestConfigStr, 'utf8')
-    .digest('hex');
-}
diff --git a/src/transpile-if-ts.ts b/src/transpile-if-ts.ts
deleted file mode 100644
index 95a2640f0e..0000000000
--- a/src/transpile-if-ts.ts
+++ /dev/null
@@ -1,23 +0,0 @@
-import * as tsc from 'typescript';
-import { getTSConfig, mockGlobalTSConfigSchema } from './utils';
-import { ConfigGlobals } from './jest-types';
-
-export function transpileIfTypescript(
-  path: string,
-  contents: string,
-  config?: ConfigGlobals,
-  rootDir: string = '',
-): string {
-  if (path && (path.endsWith('.tsx') || path.endsWith('.ts'))) {
-    const transpiled = tsc.transpileModule(contents, {
-      compilerOptions: getTSConfig(
-        config || mockGlobalTSConfigSchema(global),
-        rootDir,
-      ),
-      fileName: path,
-    });
-
-    return transpiled.outputText;
-  }
-  return contents;
-}
diff --git a/src/transpiler.ts b/src/transpiler.ts
index 06ce887b2b..8c6721d857 100644
--- a/src/transpiler.ts
+++ b/src/transpiler.ts
@@ -1,13 +1,12 @@
 import * as ts from 'typescript';
-import { logOnce } from './logger';
-import { CodeSourceMapPair } from './jest-types';
+import { logOnce } from './utils/logger';
 
 // Takes the typescript code and by whatever method configured, makes it into javascript code.
 export function transpileTypescript(
   filePath: string,
   fileSrc: string,
   compilerOptions: ts.CompilerOptions,
-): CodeSourceMapPair {
+): jest.TransformedSource {
   logOnce('Compiling via normal transpileModule call');
   const transpileOutput = transpileViaTranspileModule(
     filePath,
diff --git a/src/jest-types.ts b/src/types.ts
similarity index 65%
rename from src/jest-types.ts
rename to src/types.ts
index f3ff30693d..e6456852b1 100644
--- a/src/jest-types.ts
+++ b/src/types.ts
@@ -1,17 +1,22 @@
 import { TransformOptions as BabelTransformOpts } from 'babel-core';
 
-export interface TransformOptions {
+export interface JestCacheKeyOptions {
+  rootDir: string;
   instrument: boolean;
 }
 
-export type Path = string;
-
-export type Glob = string;
-
-export interface ConfigGlobals {
-  [key: string]: any;
+export interface TsJestContext {
+  cache: any;
+  options: any;
 }
 
+export type JestCacheKeyArguments = [
+  string,
+  string,
+  string,
+  JestCacheKeyOptions
+];
+
 export interface HasteConfig {
   defaultPlatform?: string | null;
   hasteImplModulePath?: string;
@@ -24,17 +29,11 @@ export interface BabelTransformOptions extends BabelTransformOpts {
 }
 
 export type PostProcessHook = (
-  codeSourcemapPair: CodeSourceMapPair,
+  codeSourcemapPair: jest.TransformedSource,
   filePath: string,
-  config: JestConfig,
-  transformOptions: TransformOptions,
-) => CodeSourceMapPair;
-
-export type JestConfig = jest.InitialOptions & {
-  globals?: jest.ConfigGlobals & {
-    __TRANSFORM_HTML__?: boolean;
-  };
-};
+  config: jest.ProjectConfig,
+  transformOptions: jest.TransformOptions,
+) => jest.TransformedSource;
 
 export interface TsJestConfig {
   babelConfig?: BabelTransformOpts;
@@ -53,8 +52,3 @@ export interface JestConfigNormalize {
   hasDeprecationWarnings: boolean;
   options: jest.DefaultOptions;
 }
-
-export interface CodeSourceMapPair {
-  code: string;
-  map: string;
-}
diff --git a/src/utils/constants.ts b/src/utils/constants.ts
new file mode 100644
index 0000000000..b8556ac8ac
--- /dev/null
+++ b/src/utils/constants.ts
@@ -0,0 +1,12 @@
+import { readFileSync } from 'fs';
+import { resolve } from 'path';
+
+export const BABELRC_FILENAME = '.babelrc';
+export const BABELRC_JS_FILENAME = '.babelrc.js';
+export const BABEL_CONFIG_KEY = 'babel';
+export const TSCONFIG_FILENAME = 'tsconfig.json';
+export const TSCONFIG_GLOBALS_KEY = 'ts-jest';
+export const PACKAGE_JSON = 'package.json';
+export const MY_PACKAGE_CONTENT = readFileSync(
+  resolve(__dirname, '..', '..', PACKAGE_JSON),
+);
diff --git a/src/utils/get-babel-rc.ts b/src/utils/get-babel-rc.ts
new file mode 100644
index 0000000000..b4734513a9
--- /dev/null
+++ b/src/utils/get-babel-rc.ts
@@ -0,0 +1,50 @@
+import { readFileSync, existsSync } from 'fs';
+import { dirname, join, resolve } from 'path';
+import {
+  BABELRC_FILENAME,
+  BABELRC_JS_FILENAME,
+  PACKAGE_JSON,
+  BABEL_CONFIG_KEY,
+} from './constants';
+import { TsJestContext } from '../types';
+
+// ideally we'd get that from babel-jest if it was exported,
+// this is a pure translation from js
+export default function getBabelRC(filename, { cache }: TsJestContext) {
+  const paths = [];
+  let directory = filename;
+  // tslint:disable-next-line:no-conditional-assignment
+  while (directory !== (directory = dirname(directory))) {
+    if (cache[directory]) {
+      break;
+    }
+
+    paths.push(directory);
+    const configFilePath = join(directory, BABELRC_FILENAME);
+    if (existsSync(configFilePath)) {
+      cache[directory] = readFileSync(configFilePath, 'utf8');
+      break;
+    }
+    const configJsFilePath = join(directory, BABELRC_JS_FILENAME);
+    if (existsSync(configJsFilePath)) {
+      cache[directory] = JSON.stringify(require(configJsFilePath));
+      break;
+    }
+    const resolvedJsonFilePath = join(directory, PACKAGE_JSON);
+    const packageJsonFilePath =
+      resolvedJsonFilePath === PACKAGE_JSON
+        ? resolve(directory, PACKAGE_JSON)
+        : resolvedJsonFilePath;
+    if (existsSync(packageJsonFilePath)) {
+      const packageJsonFileContents = require(packageJsonFilePath);
+      if (packageJsonFileContents[BABEL_CONFIG_KEY]) {
+        cache[directory] = JSON.stringify(
+          packageJsonFileContents[BABEL_CONFIG_KEY],
+        );
+        break;
+      }
+    }
+  }
+  paths.forEach(directoryPath => (cache[directoryPath] = cache[directory]));
+  return cache[directory] || '';
+}
diff --git a/src/utils/get-cache-key.ts b/src/utils/get-cache-key.ts
new file mode 100644
index 0000000000..d471bfe28d
--- /dev/null
+++ b/src/utils/get-cache-key.ts
@@ -0,0 +1,31 @@
+import { createHash } from 'crypto';
+import { JestCacheKeyArguments, TsJestContext } from '../types';
+import { relative, resolve } from 'path';
+import { MY_PACKAGE_CONTENT } from './constants';
+import getBabelRC from './get-babel-rc';
+import { getTSConfig } from '.';
+
+export default function getCacheKey(
+  args: JestCacheKeyArguments,
+  ctx: TsJestContext,
+): string {
+  const [fileData, filePath, jestConfigString, { instrument, rootDir }] = args;
+  const glob = JSON.parse(jestConfigString).globals || {};
+  return createHash('md5')
+    .update(MY_PACKAGE_CONTENT)
+    .update('\0', 'utf8')
+    .update(JSON.stringify(ctx.options))
+    .update('\0', 'utf8')
+    .update(fileData)
+    .update('\0', 'utf8')
+    .update(relative(rootDir, filePath))
+    .update('\0', 'utf8')
+    .update(jestConfigString)
+    .update('\0', 'utf8')
+    .update(JSON.stringify(getTSConfig(glob, rootDir)))
+    .update('\0', 'utf8')
+    .update(getBabelRC(filePath, ctx))
+    .update('\0', 'utf8')
+    .update(instrument ? 'instrument' : '')
+    .digest('hex');
+}
diff --git a/src/utils.ts b/src/utils/index.ts
similarity index 94%
rename from src/utils.ts
rename to src/utils/index.ts
index 8b9b03c198..a2c68b3365 100644
--- a/src/utils.ts
+++ b/src/utils/index.ts
@@ -3,12 +3,12 @@ import * as fs from 'fs';
 import * as fsExtra from 'fs-extra';
 import * as path from 'path';
 import * as tsc from 'typescript';
-import { ConfigGlobals, JestConfig, TsJestConfig } from './jest-types';
+import { TsJestConfig } from '../types';
 import { logOnce } from './logger';
 import * as _ from 'lodash';
 
-export function getTSJestConfig(globals: ConfigGlobals): TsJestConfig {
-  return globals && globals['ts-jest'] ? globals['ts-jest'] : {};
+export function getTSJestConfig(globals: jest.ConfigGlobals): TsJestConfig {
+  return (globals && globals['ts-jest']) || {};
 }
 
 function formatTsDiagnostics(errors: tsc.Diagnostic[]): string {
@@ -88,7 +88,7 @@ function getPathToClosestTSConfig(
 }
 
 function getTSConfigPathFromConfig(
-  globals: ConfigGlobals,
+  globals: jest.ConfigGlobals,
   rootDir?: string,
 ): string {
   const defaultTSConfigFile = getPathToClosestTSConfig(rootDir);
@@ -106,8 +106,8 @@ function getTSConfigPathFromConfig(
 }
 
 export function mockGlobalTSConfigSchema(
-  globals: ConfigGlobals,
-): ConfigGlobals {
+  globals: jest.ConfigGlobals,
+): jest.ConfigGlobals {
   const configPath = getTSConfigPathFromConfig(globals);
   return { 'ts-jest': { tsConfigFile: configPath } };
 }
@@ -161,7 +161,7 @@ function getTSConfig_local(globals, rootDir: string = '') {
 }
 
 export function cacheFile(
-  jestConfig: JestConfig,
+  jestConfig: jest.ProjectConfig,
   filePath: string,
   src: string,
 ): void {
diff --git a/src/logger.ts b/src/utils/logger.ts
similarity index 100%
rename from src/logger.ts
rename to src/utils/logger.ts
diff --git a/tests/__tests__/get-cache-key.spec.ts b/tests/__tests__/get-cache-key.spec.ts
index a85885b9e6..43e3e2e7a4 100644
--- a/tests/__tests__/get-cache-key.spec.ts
+++ b/tests/__tests__/get-cache-key.spec.ts
@@ -1,6 +1,9 @@
-import { getCacheKey } from '../../src/preprocessor';
-import { TransformOptions } from '../../src/jest-types';
+import getCacheKeyForArgs from '../../dist/utils/get-cache-key';
+import { TsJestContext } from '../../dist/types';
 
+const tsJestContext: TsJestContext = { cache: {}, options: {} };
+const getCacheKey = (...args: any[]) =>
+  getCacheKeyForArgs(args as any, tsJestContext);
 describe('getCacheKey', () => {
   const src = 'console.log(123);';
   const filepath = '/tmp/filepath';
@@ -18,7 +21,7 @@ describe('getCacheKey', () => {
     },
     "testRegex": "(/__tests__/.*|(\\\\.|/)(test|spec))\\\\.(jsx?|tsx?)$"
   }`;
-  const options: TransformOptions = { instrument: false };
+  const options: jest.TransformOptions = { instrument: false };
   const originalHash = getCacheKey(src, filepath, configStr, options);
 
   it('should change hash when src changes', () => {
@@ -40,7 +43,7 @@ describe('getCacheKey', () => {
   });
 
   it('should change hash when transform options change', () => {
-    const newOptions: TransformOptions = { instrument: true };
+    const newOptions: jest.TransformOptions = { instrument: true };
     const newHash = getCacheKey(src, filepath, configStr, newOptions);
     expect(newHash).not.toBe(originalHash);
   });
diff --git a/tests/__tests__/transpiler.spec.ts b/tests/__tests__/transpiler.spec.ts
index abaab22f45..4e10add7dc 100644
--- a/tests/__tests__/transpiler.spec.ts
+++ b/tests/__tests__/transpiler.spec.ts
@@ -2,22 +2,33 @@ import { transpileTypescript } from '../../src/transpiler';
 import * as ts from 'typescript';
 
 describe('transpileTypescript', () => {
-
-  const compilerOptions: ts.CompilerOptions = {newLine: ts.NewLineKind.LineFeed};
+  const compilerOptions: ts.CompilerOptions = {
+    newLine: ts.NewLineKind.LineFeed,
+  };
 
   it('should transpile valid TS syntax', () => {
-    const result = transpileTypescript('valid.ts', 'var a = true;', compilerOptions);
+    const result = transpileTypescript(
+      'valid.ts',
+      'var a = true;',
+      compilerOptions,
+    );
     expect(result.code).toBe('var a = true;\n');
   });
 
   it('should transpile valid TS syntax with type errors', () => {
-    const result = transpileTypescript('valid.ts', 'var a: string = true;', compilerOptions);
+    const result = transpileTypescript(
+      'valid.ts',
+      'var a: string = true;',
+      compilerOptions,
+    );
     expect(result.code).toBe('var a = true;\n');
   });
 
   it('should throw an error when transpiling invalid TS syntax', () => {
     expect(() => {
       transpileTypescript('invalid.ts', 'var a = ;', compilerOptions);
-    }).toThrow('TypeScript compiler encountered syntax errors while transpiling. Errors: Expression expected.');
+    }).toThrow(
+      'TypeScript compiler encountered syntax errors while transpiling. Errors: Expression expected.',
+    );
   });
 });
diff --git a/tests/coverage-simple/.gitignore b/tests/coverage-simple/.gitignore
new file mode 100644
index 0000000000..9e233d795a
--- /dev/null
+++ b/tests/coverage-simple/.gitignore
@@ -0,0 +1 @@
+coverage-custom
diff --git a/tests/coverage-simple/Hello.ts b/tests/coverage-simple/Hello.ts
new file mode 100644
index 0000000000..3eaae5c40d
--- /dev/null
+++ b/tests/coverage-simple/Hello.ts
@@ -0,0 +1,28 @@
+interface FooInterface {
+  foo: string;
+  bar: number; //This interface should be stripped and the line numbers should still fit.
+}
+
+export class Hello {
+  constructor() {
+    const greeting = `
+      this
+      is
+      a
+      multiline
+      greeting
+    `;
+
+    this.unexcuted(() => {});
+
+    throw new Error('Hello error!');
+  }
+
+  unexcuted(action: () => void = () => {}): void {
+    if (action) {
+      action();
+    } else {
+      console.log('unexcuted');
+    }
+  }
+}
diff --git a/tests/coverage-simple/NullCoverage.js b/tests/coverage-simple/NullCoverage.js
new file mode 100644
index 0000000000..c59dbbdef3
--- /dev/null
+++ b/tests/coverage-simple/NullCoverage.js
@@ -0,0 +1,6 @@
+function nullCoverageFunction(value) {
+  if (value) {
+    return value;
+  }
+  return null;
+}
diff --git a/tests/coverage-simple/__tests__/Hello.test.ts b/tests/coverage-simple/__tests__/Hello.test.ts
new file mode 100644
index 0000000000..3df75018f9
--- /dev/null
+++ b/tests/coverage-simple/__tests__/Hello.test.ts
@@ -0,0 +1,9 @@
+declare var jest, describe, it, expect;
+
+import { Hello } from '../Hello';
+
+describe('Hello Class', () => {
+  it('should throw an error on line 18', () => {
+    expect(() => new Hello()).toThrow();
+  });
+});
diff --git a/tests/coverage-simple/package.json b/tests/coverage-simple/package.json
new file mode 100644
index 0000000000..c577a32b44
--- /dev/null
+++ b/tests/coverage-simple/package.json
@@ -0,0 +1,22 @@
+{
+  "jest": {
+    "transform": {
+      "^.+\\.tsx?$": "ts-jest"
+    },
+    "testRegex": "(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|tsx?)$",
+    "coverageReporters": [
+      "lcov"
+    ],
+    "collectCoverageFrom": [
+      "Hello.ts",
+      "NullCoverage.js"
+    ],
+    "moduleFileExtensions": [
+      "ts",
+      "tsx",
+      "js",
+      "jsx",
+      "json"
+    ]
+  }
+}
diff --git a/tests/coverage-simple/tsconfig.json b/tests/coverage-simple/tsconfig.json
new file mode 100644
index 0000000000..55f8667f97
--- /dev/null
+++ b/tests/coverage-simple/tsconfig.json
@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {
+    "target": "ES5",
+    "module": "commonjs",
+    "moduleResolution": "node",
+    "noEmitOnError": false,
+    "jsx": "react",
+    "allowJs": true
+  }
+}
diff --git a/tests/coverage-simple/yarn.lock b/tests/coverage-simple/yarn.lock
new file mode 100644
index 0000000000..fb57ccd13a
--- /dev/null
+++ b/tests/coverage-simple/yarn.lock
@@ -0,0 +1,4 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
diff --git a/tsconfig.build.json b/tsconfig.build.json
new file mode 100644
index 0000000000..4eecabd0b4
--- /dev/null
+++ b/tsconfig.build.json
@@ -0,0 +1,11 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "sourceMap": false,
+    "removeComments": true,
+    "outDir": "dist",
+    "rootDir": "src",
+  },
+  "include": ["src/**/*.ts"],
+  "exclude": ["node_modules"]
+}
diff --git a/tsconfig.json b/tsconfig.json
index d5b6e37db0..d1a8c133ba 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
     "sourceMap": false,
+    "inlineSourceMap": true,
     "declaration": true,
     "target": "es5",
     "module": "commonjs",
@@ -11,17 +12,13 @@
     "noImplicitReturns": true,
     "removeComments": true,
     "strictNullChecks": false,
-    "inlineSourceMap": true,
     "jsx": "react",
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
     "allowSyntheticDefaultImports": false,
-    "outDir": "dist",
-    "rootDir": "src",
     "skipLibCheck": true,
     "lib": ["es2015"],
     "types": ["jest"]
   },
-  "include": ["src/**/*.ts", "src/**/*.tsx"],
-  "exclude": ["node_modules"]
+  "exclude": ["**/node_modules/**/*"]
 }