Add snapshot testing for error messages

Author: Walker

test/__snapshots__/writer.test.js.snap

@@ -0,0 +1,15 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`new Writer([filePath]) ensures filePath is not an object 1`] = `"Expected 'files' to be of type 'Array' or a 'string', instead got 'undefined'"`;
+
+exports[`new Writer([filePath]) ensures filePath[] is an array of strings 1`] = `"Expected 'file' (null) to be of type 'string', instead got 'object'"`;
+
+exports[`new Writer([filePath]) ensures filePath[] is not a number 1`] = `"Expected 'files' to be of type 'Array' or a 'string', instead got 'undefined'"`;
+
+exports[`new Writer([filePath]) ensures filePath[] is not null 1`] = `"Expected 'files' to be of type 'Array' or a 'string', instead got 'undefined'"`;
+
+exports[`new Writer([filePath]) ensures valid filePath provided 1`] = `"Expected 'file' (fake.css) to be an absolute path to a file but it was not"`;
+
+exports[`new Writer([filePath]) ensures valid filePaths provided in array 1`] = `"Expected 'file' (fake.css) to be an absolute path to a file but it was not"`;
+
+exports[`new Writer(filePath) relative paths throw error 1`] = `"Expected 'file' (./test-assets/my-module-1/main.css) to be an absolute path to a file but it was not"`;

test/writer.test.js

@@ -82,7 +82,7 @@ test('new Writer(filePath) relative paths throw error', () => {
 
     const result = () => new Writer(filePath);
 
-    expect(result).toThrow();
+    expect(result).toThrowErrorMatchingSnapshot();
 });
 
 test('new Writer([filePath])', done => {
@@ -163,7 +163,7 @@ test('new Writer([filePath]) ensures filePath[] is not null', () => {
 
     const result = () => new Writer(filePath);
 
-    expect(result).toThrow();
+    expect(result).toThrowErrorMatchingSnapshot();
 });
 
 test('new Writer([filePath]) ensures filePath[] is not a number', () => {
@@ -172,7 +172,7 @@ test('new Writer([filePath]) ensures filePath[] is not a number', () => {
 
     const result = () => new Writer(filePath);
 
-    expect(result).toThrow();
+    expect(result).toThrowErrorMatchingSnapshot();
 });
 
 test('new Writer([filePath]) ensures filePath is not an object', () => {
@@ -181,7 +181,7 @@ test('new Writer([filePath]) ensures filePath is not an object', () => {
 
     const result = () => new Writer(filePath);
 
-    expect(result).toThrow();
+    expect(result).toThrowErrorMatchingSnapshot();
 });
 
 test('new Writer([filePath]) ensures filePath[] is an array of strings', () => {
@@ -190,7 +190,7 @@ test('new Writer([filePath]) ensures filePath[] is an array of strings', () => {
 
     const result = () => new Writer([filePath]);
 
-    expect(result).toThrow();
+    expect(result).toThrowErrorMatchingSnapshot();
 });
 
 test('new Writer([filePath]) ensures valid filePath provided', () => {
@@ -199,7 +199,7 @@ test('new Writer([filePath]) ensures valid filePath provided', () => {
 
     const result = () => new Writer(filePath);
 
-    expect(result).toThrow();
+    expect(result).toThrowErrorMatchingSnapshot();
 });
 
 test('new Writer([filePath]) ensures valid filePaths provided in array', () => {
@@ -208,7 +208,7 @@ test('new Writer([filePath]) ensures valid filePaths provided in array', () => {
 
     const result = () => new Writer([filePath]);
 
-    expect(result).toThrow();
+    expect(result).toThrowErrorMatchingSnapshot();
 });
 
 test('writer emits error', done => {