test: add snapshot toHaveStyle diff output (#42)

Author: philipbulley

src/__tests__/__snapshots__/to-have-style.js.snap

@@ -0,0 +1,28 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`.toHaveStyle handles negative test cases 1`] = `
+"<dim>expect(</><red>element</><dim>).toHaveStyle()</>
+
+<green>- Expected</>
+
+<dim>  backgroundColor: blue;</>
+<dim>  transform: [</>
+<dim>    {</>
+<green>-     \\"scale\\": 1</>
+<red>+     \\"scale\\": 2</>
+<dim>    }</>
+<dim>  ];</>"
+`;
+
+exports[`.toHaveStyle handles transform when transform undefined 1`] = `
+"<dim>expect(</><red>element</><dim>).toHaveStyle()</>
+
+<green>- Expected</>
+
+<green>- transform: [</>
+<green>-   {</>
+<green>-     \\"scale\\": 1</>
+<green>-   }</>
+<green>- ];</>
+<red>+ transform: undefined;</>"
+`;

src/__tests__/to-have-style.js

@@ -52,7 +52,7 @@ describe('.toHaveStyle', () => {
     const container = getByTestId('container');
     expect(() =>
       expect(container).toHaveStyle({ backgroundColor: 'blue', transform: [{ scale: 1 }] }),
-    ).toThrowError();
+    ).toThrowErrorMatchingSnapshot();
     expect(() => expect(container).toHaveStyle({ fontWeight: 'bold' })).toThrowError();
     expect(() => expect(container).not.toHaveStyle({ color: 'black' })).toThrowError();
   });
@@ -83,6 +83,8 @@ describe('.toHaveStyle', () => {
     );
 
     const container = getByTestId('container');
-    expect(() => expect(container).toHaveStyle({ transform: [{ scale: 1 }] })).toThrowError();
+    expect(() =>
+      expect(container).toHaveStyle({ transform: [{ scale: 1 }] }),
+    ).toThrowErrorMatchingSnapshot();
   });
 });