stop typechecking tsickle output

Summary:
We need to be able to generate invalid TypeScript.

Drop typechecking of tsickle output from the test suite.
Note that we still Closure-compile the tsickle output so the
output is still checked; it's just that sometimes we're gonna
want to do things that TypeScript disallows, like reach past
a "private" modifier, to make Closure work.

See issue #189.

Reviewers: rkirov

Reviewed By: rkirov

Subscribers: typescript-eng

Differential Revision: https://reviews.angular.io/D214

Author: evmar

test/test_support.ts

@@ -10,7 +10,6 @@ import * as tsickle from '../src/tsickle';
 const compilerOptions: ts.CompilerOptions = {
   target: ts.ScriptTarget.ES6,
   skipDefaultLibCheck: true,
-  noEmitOnError: true,
   experimentalDecorators: true,
   emitDecoratorMetadata: true,
   noEmitHelpers: true,
@@ -28,7 +27,7 @@ const {cachedLibPath, cachedLib} = (function() {
   return {cachedLibPath: p, cachedLib: host.getSourceFile(fn, ts.ScriptTarget.ES6)};
 })();
 
-/** Creates a ts.Program from a set of input files.  Throws an exception on errors. */
+/** Creates a ts.Program from a set of input files. */
 export function createProgram(sources: {[fileName: string]: string}): ts.Program {
   let host = ts.createCompilerHost(compilerOptions);
 
@@ -53,23 +52,17 @@ export function createProgram(sources: {[fileName: string]: string}): ts.Program
     throw new Error('unexpected file read of ' + fileName + ' not in ' + Object.keys(sources));
   };
 
-  let program = ts.createProgram(Object.keys(sources), compilerOptions, host);
-  let diagnostics = ts.getPreEmitDiagnostics(program);
-  if (diagnostics.length) {
-    throw new Error(tsickle.formatDiagnostics(diagnostics));
-  }
-
-  return program;
+  return ts.createProgram(Object.keys(sources), compilerOptions, host);
 }
 
 /** Emits transpiled output with tsickle postprocessing.  Throws an exception on errors. */
-export function emit(program: ts.Program): {[fileName: string]: string} {
+export function emit(program: ts.Program, checkErrors = true): {[fileName: string]: string} {
   let transformed: {[fileName: string]: string} = {};
   let emitRes = program.emit(undefined, (fileName: string, data: string) => {
     transformed[fileName] =
         tsickle.convertCommonJsToGoogModule(fileName, data, cliSupport.pathToModuleName).output;
   });
-  if (emitRes.diagnostics.length) {
+  if (checkErrors && emitRes.diagnostics.length) {
     throw new Error(tsickle.formatDiagnostics(emitRes.diagnostics));
   }
   return transformed;

test/tsickle_test.ts

@@ -138,7 +138,7 @@ describe('golden tests', () => {
       // Run tsickled TypeScript through TypeScript compiler
       // and compare against goldens.
       program = testSupport.createProgram(tsickleSources);
-      let jsSources = testSupport.emit(program);
+      let jsSources = testSupport.emit(program, /* ignore errors */ false);
       for (let jsPath of Object.keys(jsSources)) {
         compareAgainstGolden(jsSources[jsPath], jsPath);
       }