more

packages/expect/src/__tests__/__snapshots__/extend.test.js.snap

@@ -1,6 +1,42 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`defines asymmetric matchers 1`] = `"val.toAsymmetricMatcher is not a function"`;
+exports[`defines asymmetric matchers 1`] = `
+"<dim>expect(</><red>received</><dim>).toEqual(</><green>expected</><dim>)</>
+
+Expected value to equal:
+  <green>{\\"value\\": toBeDivisibleBy<2>}</>
+Received:
+  <red>{\\"value\\": 3}</>
+
+Difference:
+
+<green>- Expected</>
+<red>+ Received</>
+
+<dim>  Object {</>
+<green>-   \\"value\\": toBeDivisibleBy<2>,</>
+<red>+   \\"value\\": 3,</>
+<dim>  }</>"
+`;
+
+exports[`defines asymmetric matchers that can be prefixed by not 1`] = `
+"<dim>expect(</><red>received</><dim>).toEqual(</><green>expected</><dim>)</>
+
+Expected value to equal:
+  <green>{\\"value\\": not.toBeDivisibleBy<2>}</>
+Received:
+  <red>{\\"value\\": 2}</>
+
+Difference:
+
+<green>- Expected</>
+<red>+ Received</>
+
+<dim>  Object {</>
+<green>-   \\"value\\": not.toBeDivisibleBy<2>,</>
+<red>+   \\"value\\": 2,</>
+<dim>  }</>"
+`;
 
 exports[`is available globally 1`] = `"expected 15 to be divisible by 2"`;
 

packages/expect/src/__tests__/extend.test.js

@@ -72,12 +72,19 @@ it('exposes an equality function to custom matchers', () => {
 });
 
 it('defines asymmetric matchers', () => {
-  jestExpect({value: 2}).toEqual({value: jestExpect.toBeDivisibleBy(2)});
+  expect(() =>
+    jestExpect({value: 2}).toEqual({value: jestExpect.toBeDivisibleBy(2)}),
+  ).not.toThrow();
   expect(() =>
     jestExpect({value: 3}).toEqual({value: jestExpect.toBeDivisibleBy(2)}),
   ).toThrowErrorMatchingSnapshot();
 });
 
 it('defines asymmetric matchers that can be prefixed by not', () => {
-  jestExpect({value: 3}).toEqual({value: jestExpect.not.toBeDivisibleBy(2)});
+  expect(() =>
+    jestExpect({value: 2}).toEqual({value: jestExpect.not.toBeDivisibleBy(2)}),
+  ).toThrowErrorMatchingSnapshot();
+  expect(() =>
+    jestExpect({value: 3}).toEqual({value: jestExpect.not.toBeDivisibleBy(2)}),
+  ).not.toThrow();
 });

packages/expect/src/jest_matchers_object.js

@@ -57,9 +57,10 @@ export const setMatchers = (
       class CustomMatcher extends AsymmetricMatcher {
         sample: any;
 
-        constructor(sample: any) {
+        constructor(sample: any, inverse: boolean = false) {
           super();
           this.sample = sample;
+          this.inverse = inverse;
         }
 
         asymmetricMatch(other: any) {
@@ -68,19 +69,24 @@ export const setMatchers = (
             (this.sample: any),
           );
 
-          return pass;
+          return this.inverse ? !pass : pass;
         }
 
         toString() {
-          return key;
+          return `${this.inverse ? 'not.' : ''}${key}`;
         }
 
         getExpectedType() {
           return 'any';
         }
+
+        toAsymmetricMatcher() {
+          return `${this.toString()}<${this.sample}>`;
+        }
       }
 
       expect[key] = (sample: any) => new CustomMatcher(sample);
+      expect.not[key] = (sample: any) => new CustomMatcher(sample, true);
     }
   });