Make Flow Parser snapshots more readable

Summary:
The Flow Parser's snapshots, which are serializations of the CodegenSchema object, are extremely difficult to read. In this diff, I explicitly serialized the schema objects using Node's `util.inspect`.

**Benefits:**
- The snapshots are more readable now.
- You can copy-paste the objects from the snapshot files directly into the Chrome console, or into other JavaScript files. This is a very useful feature, when we're testing the generators, or other infra that depends on the codegen.

Changelog: [Internal]

Reviewed By: hramos

Differential Revision: D24063112

fbshipit-source-id: 2c6ec3424aac8bab2688dc6ae286b73f90e4bef1

packages/react-native-codegen/src/parsers/flow/components/__tests__/component-parser-test.js

@@ -14,6 +14,7 @@
 const FlowParser = require('../../index.js');
 const fixtures = require('../__test_fixtures__/fixtures.js');
 const failureFixtures = require('../__test_fixtures__/failures.js');
+const util = require('util');
 jest.mock('fs', () => ({
   readFileSync: filename => fixtures[filename] || failureFixtures[filename],
 }));
@@ -23,7 +24,12 @@ describe('RN Codegen Flow Parser', () => {
     .sort()
     .forEach(fixtureName => {
       it(`can generate fixture ${fixtureName}`, () => {
-        expect(FlowParser.parseFile(fixtureName)).toMatchSnapshot();
+        const schema = FlowParser.parseFile(fixtureName);
+        const serializedSchema = util.inspect(schema, {
+          showHidden: false,
+          depth: null,
+        });
+        expect(serializedSchema).toMatchSnapshot();
       });
     });
 

packages/react-native-codegen/src/parsers/flow/modules/__tests__/module-parser-snapshot-test.js

@@ -14,6 +14,7 @@
 const FlowParser = require('../../index.js');
 const fixtures = require('../__test_fixtures__/fixtures.js');
 const failureFixtures = require('../__test_fixtures__/failures.js');
+const util = require('util');
 jest.mock('fs', () => ({
   readFileSync: filename => fixtures[filename] || failureFixtures[filename],
 }));
@@ -23,7 +24,13 @@ describe('RN Codegen Flow Parser', () => {
     .sort()
     .forEach(fixtureName => {
       it(`can generate fixture ${fixtureName}`, () => {
-        expect(FlowParser.parseModuleFixture(fixtureName)).toMatchSnapshot();
+        const schema = FlowParser.parseModuleFixture(fixtureName);
+        const serializedSchema = util.inspect(schema, {
+          showHidden: false,
+          depth: null,
+        });
+
+        expect(serializedSchema).toMatchSnapshot();
       });
     });