add invoke() api to shallow and mount

SUMMARY.md

@@ -48,6 +48,7 @@
     * [hostNodes()](/docs/api/ShallowWrapper/hostNodes.md)
     * [html()](/docs/api/ShallowWrapper/html.md)
     * [instance()](/docs/api/ShallowWrapper/instance.md)
+    * [invoke(propName[, ...args])](/docs/api/ShallowWrapper/invoke.md)
     * [is(selector)](/docs/api/ShallowWrapper/is.md)
     * [isEmpty()](/docs/api/ShallowWrapper/isEmpty.md)
     * [isEmptyRender()](/docs/api/ShallowWrapper/isEmptyRender.md)
@@ -108,6 +109,7 @@
     * [hostNodes()](/docs/api/ReactWrapper/hostNodes.md)
     * [html()](/docs/api/ReactWrapper/html.md)
     * [instance()](/docs/api/ReactWrapper/instance.md)
+    * [invoke(propName[, ...args])](/docs/api/ReactWrapper/invoke.md)
     * [is(selector)](/docs/api/ReactWrapper/is.md)
     * [isEmpty()](/docs/api/ReactWrapper/isEmpty.md)
     * [isEmptyRender()](/docs/api/ReactWrapper/isEmptyRender.md)

docs/api/ReactWrapper/invoke.md

@@ -0,0 +1,38 @@
+# `.invoke(propName[, ...args]) => Any`
+
+ Invokes a function prop.
+
+ #### Arguments
+
+ 1. `propName` (`String`): The function prop to be invoked
+2. `...args` (`Any` [optional]): Arguments that will be passed to the prop function
+
+ #### Returns
+
+ `Any`: Returns the value from the prop function
+
+ #### Example
+
+ ```jsx
+class Foo extends React.Component {
+  loadData() {
+    return fetch();
+  }
+   render() {
+    return (
+      <div>
+        <button
+          type="button"
+          onClick={() => this.loadData()}
+        >
+          Load more
+        </button>
+      </div>
+    );
+  }
+}
+ const wrapper = mount(<Foo />);
+ wrapper.find('a').invoke('onClick').then(() => {
+  // expect()
+});
+```

docs/api/ShallowWrapper/invoke.md

@@ -0,0 +1,38 @@
+# `.invoke(invokeName[, ...args]) => Any`
+
+ Invokes a function prop.
+
+ #### Arguments
+
+ 1. `propName` (`String`): The function prop to be invoked
+2. `...args` (`Any` [optional]): Arguments that will be passed to the prop function
+
+ #### Returns
+
+ `Any`: Returns the value from the prop function
+
+ #### Example
+
+ ```jsx
+class Foo extends React.Component {
+  loadData() {
+    return fetch();
+  }
+   render() {
+    return (
+      <div>
+        <button
+          type="button"
+          onClick={() => this.loadData()}
+        >
+          Load more
+        </button>
+      </div>
+    );
+  }
+}
+ const wrapper = shallow(<Foo />);
+ wrapper.find('a').invoke('onClick').then(() => {
+  // expect()
+});
+```

docs/api/mount.md

@@ -159,6 +159,9 @@ Returns the props of the root component.
 #### [`.prop(key) => Any`](ReactWrapper/prop.md)
 Returns the named prop of the root component.
 
+#### [`.invoke(propName[, ...args]) => Any`](ReactWrapper/invoke.md)
+Invokes a prop function on the current node and returns the function's return value.
+
 #### [`.key() => String`](ReactWrapper/key.md)
 Returns the key of the root component.
 

docs/api/shallow.md

@@ -175,6 +175,9 @@ Returns the named prop of the current node.
 #### [`.key() => String`](ShallowWrapper/key.md)
 Returns the key of the current node.
 
+#### [`.invoke(propName[, ...args]) => Any`](ShallowWrapper/invoke.md)
+Invokes a prop function on the current node and returns the function's return value.
+
 #### [`.simulate(event[, data]) => ShallowWrapper`](ShallowWrapper/simulate.md)
 Simulates an event on the current node.
 

packages/enzyme-test-suite/package.json

@@ -57,4 +57,4 @@
     "eslint-plugin-react": "^7.12.4",
     "react-is": "^16.7.0"
   }
-}
+}

packages/enzyme-test-suite/test/ReactWrapper-spec.jsx

@@ -5408,6 +5408,70 @@ describeWithDOM('mount', () => {
     });
   });
 
+  describe('.invoke(propName, ..args)', () => {
+    it('can update the state value', () => {
+      class Foo extends React.Component {
+        constructor(props) {
+          super(props);
+          this.state = {
+            count: 0,
+          };
+        }
+
+        render() {
+          const { count } = this.state;
+          return (
+            <div>
+              <button
+                type="button"
+                onClick={() => this.setState(state => ({ count: state.count + 1 }))}
+              >
+                {count}
+              </button>
+            </div>
+          );
+        }
+      }
+      const wrapper = mount(<Foo />);
+      wrapper.find('button').invoke('onClick');
+      expect(wrapper.state('count')).to.equal(1);
+    });
+    it('can return the handlers return value', () => {
+      const spy = sinon.stub().returns(123);
+      class Foo extends React.Component {
+        render() {
+          return (
+            <div>
+              <a onClick={spy}>foo</a>
+            </div>
+          );
+        }
+      }
+      const wrapper = mount(<Foo />);
+      const value = wrapper.find('a').invoke('onClick');
+      expect(value).to.equal(123);
+      expect(spy.called).to.equal(true);
+    });
+    it('can pass in arguments', () => {
+      const spy = sinon.spy();
+      class Foo extends React.Component {
+        render() {
+          return (
+            <div>
+              <a onClick={spy}>foo</a>
+            </div>
+          );
+        }
+      }
+      const wrapper = mount(<Foo />);
+      const a = {};
+      const b = {};
+      wrapper.find('a').invoke('onClick', a, b);
+      expect(spy.args[0][0]).to.equal(a);
+      expect(spy.args[0][1]).to.equal(b);
+    });
+  });
+
   wrap()
     .withConsoleThrows()
     .describe('.renderProp()', () => {

packages/enzyme-test-suite/test/ShallowWrapper-spec.jsx

@@ -5489,6 +5489,70 @@ describe('shallow', () => {
     });
   });
 
+  describe('.invoke(propName, ..args)', () => {
+    it('can update the state value', () => {
+      class Foo extends React.Component {
+        constructor(props) {
+          super(props);
+          this.state = {
+            count: 0,
+          };
+        }
+
+         render() {
+          const { count } = this.state;
+          return (
+            <div>
+              <button
+                type="button"
+                onClick={() => this.setState(state => ({ count: state.count + 1 }))}
+              >
+                {count}
+              </button>
+            </div>
+          );
+        }
+      }
+      const wrapper = shallow(<Foo />);
+      wrapper.find('button').invoke('onClick');
+      expect(wrapper.state('count')).to.equal(1);
+    });
+    it('can return the handlers return value', () => {
+      const spy = sinon.stub().returns(123);
+      class Foo extends React.Component {
+         render() {
+          return (
+            <div>
+              <button onClick={spy}>foo</button>
+            </div>
+          );
+        }
+      }
+      const wrapper = shallow(<Foo />);
+      const value = wrapper.find('button').invoke('onClick');
+      expect(value).to.equal(123);
+      expect(spy.called).to.equal(true);
+    });
+    it('can pass in arguments', () => {
+      const spy = sinon.spy();
+      class Foo extends React.Component {
+        render() {
+          return (
+            <div>
+              <button onClick={spy}>foo</button>
+            </div>
+          );
+        }
+      }
+      const wrapper = shallow(<Foo />);
+      const a = {};
+      const b = {};
+      wrapper.find('button').invoke('onClick', a, b);
+      expect(spy.args[0][0]).to.equal(a);
+      expect(spy.args[0][1]).to.equal(b);
+    });
+  });
+
   wrap()
     .withConsoleThrows()
     .describe('.renderProp()', () => {

packages/enzyme/src/ReactWrapper.js

@@ -802,6 +802,26 @@ class ReactWrapper {
     return this.props()[propName];
   }
 
+  /**
+   * Used to invoke a function prop.
+   * Will invoke an function prop and return its value.
+   *
+   * @param {String} propName
+   * @param {Array} args
+   * @returns {Any}
+   */
+  invoke(propName, ...args) {
+    return this.single('invoke', () => {
+      const handler = this.prop(propName);
+      if (typeof handler !== 'function') {
+        throw new TypeError('ReactWrapper::invoke() expects a function prop name as its first argument');
+      }
+      const response = handler.apply(this, args);
+      this[ROOT].update();
+      return response;
+    });
+  }
+
   /**
    * Returns a wrapper of the node rendered by the provided render prop.
    *

packages/enzyme/src/ShallowWrapper.js

@@ -1132,6 +1132,26 @@ class ShallowWrapper {
     return this.props()[propName];
   }
 
+  /**
+   * Used to invoke a function prop.
+   * Will invoke an function prop and return its value.
+   *
+   * @param {String} propName
+   * @param {Array} args
+   * @returns {Any}
+   */
+  invoke(propName, ...args) {
+    return this.single('invoke', () => {
+      const handler = this.prop(propName);
+      if (typeof handler !== 'function') {
+        throw new TypeError('ShallowWrapper::invoke() expects a function prop name as its first argument');
+      }
+      const response = handler.apply(this, args);
+      this[ROOT].update();
+      return response;
+    });
+  }
+
   /**
    * Returns a wrapper of the node rendered by the provided render prop.
    *