Enable no-unused-expressions ESLint rule

This enables the `no-unused-expressions` ESLint rule and fixes the
corresponding violations. In fixing the errors I stumbled upon two
tests that were broken. After discussing with @lelandrichardson, I've
inverted the test case as the current behavior is the desired behavior.

README.md

@@ -65,7 +65,7 @@ describe('<MyComponent />', () => {
         <div className="unique" />
       </MyComponent>
     );
-    expect(wrapper.contains(<div className="unique" />)).to.be.true;
+    expect(wrapper.contains(<div className="unique" />)).to.equal(true);
   });
 
   it('simulates click events', () => {
@@ -74,7 +74,7 @@ describe('<MyComponent />', () => {
       <Foo onButtonClick={onButtonClick} />
     );
     wrapper.find('button').simulate('click');
-    expect(onButtonClick.calledOnce).to.be.true;
+    expect(onButtonClick.calledOnce).to.equal(true);
   });
 
 });
@@ -98,7 +98,7 @@ describeWithDOM('<Foo />', () => {
   it('calls componentDidMount', () => {
     spyLifecycle(Foo);
     const wrapper = mount(<Foo />);
-    expect(Foo.prototype.componentDidMount.calledOnce).to.be.true;
+    expect(Foo.prototype.componentDidMount.calledOnce).to.equal(true);
   });
 
   it('allows us to set props', () => {
@@ -114,7 +114,7 @@ describeWithDOM('<Foo />', () => {
       <Foo onButtonClick={onButtonClick} />
     );
     wrapper.find('button').simulate('click');
-    expect(onButtonClick.calledOnce).to.be.true;
+    expect(onButtonClick.calledOnce).to.equal(true);
   });
 
 });

docs/api/ReactWrapper/contains.md

@@ -23,7 +23,7 @@ like the one passed in.
 
 ```jsx
 const wrapper = mount(<MyComponent />);
-expect(wrapper.contains(<div className="foo bar" />)).to.be.true;
+expect(wrapper.contains(<div className="foo bar" />)).to.equal(true);
 ```
 
 

docs/api/ReactWrapper/every.md

@@ -25,9 +25,9 @@ const wrapper = mount(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').every('.foo')).to.be.true;
-expect(wrapper.find('.foo').every('.qoo')).to.be.false;
-expect(wrapper.find('.foo').every('.bar')).to.be.false;
+expect(wrapper.find('.foo').every('.foo')).to.equal(true);
+expect(wrapper.find('.foo').every('.qoo')).to.equal(false);
+expect(wrapper.find('.foo').every('.bar')).to.equal(false);
 ```
 
 #### Related Methods

docs/api/ReactWrapper/everyWhere.md

@@ -25,9 +25,9 @@ const wrapper = mount(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').everyWhere(n => n.hasClass('foo'))).to.be.true;
-expect(wrapper.find('.foo').everyWhere(n => n.hasClass('qoo'))).to.be.false;
-expect(wrapper.find('.foo').everyWhere(n => n.hasClass('bar'))).to.be.false;
+expect(wrapper.find('.foo').everyWhere(n => n.hasClass('foo'))).to.equal(true);
+expect(wrapper.find('.foo').everyWhere(n => n.hasClass('qoo'))).to.equal(false);
+expect(wrapper.find('.foo').everyWhere(n => n.hasClass('bar'))).to.equal(false);
 ```
 
 

docs/api/ReactWrapper/forEach.md

@@ -30,7 +30,7 @@ const wrapper = mount(
 );
 
 wrapper.find('.foo').forEach(function (node) {
-  expect(s.hasClass('foo')).to.be true;
+  expect(s.hasClass('foo')).to.equal(true);
 });
 ```
 

docs/api/ReactWrapper/hasClass.md

@@ -20,7 +20,7 @@ Returns whether or not the current node has a `className` prop including the pas
 
 ```jsx
 const wrapper = mount(<MyComponent />);
-expect(wrapper.find('.my-button').hasClass('disabled')).to.be.true;
+expect(wrapper.find('.my-button').hasClass('disabled')).to.equal(true);
 ```
 
 ### Common Gotchas

docs/api/ReactWrapper/is.md

@@ -20,6 +20,6 @@ Returns whether or not the current node matches a provided selector.
 
 ```jsx
 const wrapper = mount(<div className="some-class other-class" />);
-expect(wrapper.is('.some-class')).to.be.true;
+expect(wrapper.is('.some-class')).to.equal(true);
 ```
 

docs/api/ReactWrapper/parent.md

@@ -13,7 +13,7 @@ Returns a wrapper with the direct parent of the node in the current wrapper.
 
 ```jsx
 const wrapper = mount(<ToDoList />);
-expect(wrapper.find('ul').parent().is('div')).to.be.true;;
+expect(wrapper.find('ul').parent().is('div')).to.equal(true);
 ```
 
 #### Related Methods

docs/api/ReactWrapper/setProps.md

@@ -46,9 +46,9 @@ expect(wrapper.find('.bar')).to.have.length(1);
 const spy = sinon.spy(MyComponent.prototype, 'componentWillReceiveProps');
 
 const wrapper = mount(<MyComponent foo="bar" />);
-expect(spy.calledOnce).to.be.false;
+expect(spy.calledOnce).to.equal(false);
 wrapper.setProps({ foo: 'foo' });
-expect(spy.calledOnce).to.be.true;
+expect(spy.calledOnce).to.equal(true);
 ```
 
 

docs/api/ReactWrapper/some.md

@@ -25,9 +25,9 @@ const wrapper = mount(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').some('.qoo')).to.be.true;
-expect(wrapper.find('.foo').some('.foo')).to.be.true;
-expect(wrapper.find('.foo').some('.bar')).to.be.false;
+expect(wrapper.find('.foo').some('.qoo')).to.equal(true);
+expect(wrapper.find('.foo').some('.foo')).to.equal(true);
+expect(wrapper.find('.foo').some('.bar')).to.equal(false);
 ```
 
 #### Related Methods

docs/api/ReactWrapper/someWhere.md

@@ -25,9 +25,9 @@ const wrapper = mount(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').someWhere(n => n.hasClass('qoo'))).to.be.true;
-expect(wrapper.find('.foo').someWhere(n => n.hasClass('foo'))).to.be.true;
-expect(wrapper.find('.foo').someWhere(n => n.hasClass('bar'))).to.be.false;
+expect(wrapper.find('.foo').someWhere(n => n.hasClass('qoo'))).to.equal(true);
+expect(wrapper.find('.foo').someWhere(n => n.hasClass('foo'))).to.equal(true);
+expect(wrapper.find('.foo').someWhere(n => n.hasClass('bar'))).to.equal(false);
 ```
 
 

docs/api/ShallowWrapper/contains.md

@@ -23,7 +23,7 @@ like the one passed in.
 
 ```jsx
 const wrapper = shallow(<MyComponent />);
-expect(wrapper.contains(<div className="foo bar" />)).to.be.true;
+expect(wrapper.contains(<div className="foo bar" />)).to.equal(true);
 ```
 
 

docs/api/ShallowWrapper/every.md

@@ -25,9 +25,9 @@ const wrapper = shallow(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').every('.foo')).to.be.true;
-expect(wrapper.find('.foo').every('.qoo')).to.be.false;
-expect(wrapper.find('.foo').every('.bar')).to.be.false;
+expect(wrapper.find('.foo').every('.foo')).to.equal(true);
+expect(wrapper.find('.foo').every('.qoo')).to.equal(false);
+expect(wrapper.find('.foo').every('.bar')).to.equal(false);
 ```
 
 #### Related Methods

docs/api/ShallowWrapper/everyWhere.md

@@ -25,9 +25,9 @@ const wrapper = shallow(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').everyWhere(n => n.hasClass('foo'))).to.be.true;
-expect(wrapper.find('.foo').everyWhere(n => n.hasClass('qoo'))).to.be.false;
-expect(wrapper.find('.foo').everyWhere(n => n.hasClass('bar'))).to.be.false;
+expect(wrapper.find('.foo').everyWhere(n => n.hasClass('foo'))).to.equal(true);
+expect(wrapper.find('.foo').everyWhere(n => n.hasClass('qoo'))).to.equal(false);
+expect(wrapper.find('.foo').everyWhere(n => n.hasClass('bar'))).to.equal(false);
 ```
 
 

docs/api/ShallowWrapper/hasClass.md

@@ -20,7 +20,7 @@ Returns whether or not the current node has a `className` prop including the pas
 
 ```jsx
 const wrapper = shallow(<MyComponent />);
-expect(wrapper.find('.my-button').hasClass('disabled')).to.be.true;
+expect(wrapper.find('.my-button').hasClass('disabled')).to.equal(true);
 ```
 
 ### Common Gotchas

docs/api/ShallowWrapper/is.md

@@ -20,6 +20,6 @@ Returns whether or not the current node matches a provided selector.
 
 ```jsx
 const wrapper = shallow(<div className="some-class other-class" />);
-expect(wrapper.is('.some-class')).to.be.true;
+expect(wrapper.is('.some-class')).to.equal(true);
 ```
 

docs/api/ShallowWrapper/parent.md

@@ -2,18 +2,15 @@
 
 Returns a wrapper with the direct parent of the node in the current wrapper.
 
-
 #### Returns
 
 `ShallowWrapper`: A new wrapper that wraps the resulting nodes.
 
-
-
 #### Examples
 
 ```jsx
 const wrapper = shallow(<ToDoList />);
-expect(wrapper.find('ul').parent().is('div')).to.be.true;;
+expect(wrapper.find('ul').parent().is('div')).to.equal(true);
 ```
 
 #### Related Methods

docs/api/ShallowWrapper/setProps.md

@@ -46,9 +46,9 @@ expect(wrapper.find('.bar')).to.have.length(1);
 const spy = sinon.spy(MyComponent.prototype, 'componentWillReceiveProps');
 
 const wrapper = shallow(<MyComponent foo="bar" />);
-expect(spy.calledOnce).to.be.false;
+expect(spy.calledOnce).to.equal(false);
 wrapper.setProps({ foo: 'foo' });
-expect(spy.calledOnce).to.be.true;
+expect(spy.calledOnce).to.equal(true);
 ```
 
 

docs/api/ShallowWrapper/some.md

@@ -25,9 +25,9 @@ const wrapper = shallow(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').some('.qoo')).to.be.true;
-expect(wrapper.find('.foo').some('.foo')).to.be.true;
-expect(wrapper.find('.foo').some('.bar')).to.be.false;
+expect(wrapper.find('.foo').some('.qoo')).to.equal(true);
+expect(wrapper.find('.foo').some('.foo')).to.equal(true);
+expect(wrapper.find('.foo').some('.bar')).to.equal(false);
 ```
 
 #### Related Methods

docs/api/ShallowWrapper/someWhere.md

@@ -25,9 +25,9 @@ const wrapper = shallow(
     <div className="foo hoo" />
   </div>
 );
-expect(wrapper.find('.foo').someWhere(n => n.hasClass('qoo'))).to.be.true;
-expect(wrapper.find('.foo').someWhere(n => n.hasClass('foo'))).to.be.true;
-expect(wrapper.find('.foo').someWhere(n => n.hasClass('bar'))).to.be.false;
+expect(wrapper.find('.foo').someWhere(n => n.hasClass('qoo'))).to.equal(true);
+expect(wrapper.find('.foo').someWhere(n => n.hasClass('foo'))).to.equal(true);
+expect(wrapper.find('.foo').someWhere(n => n.hasClass('bar'))).to.equal(false);
 ```
 
 

docs/api/mount.md

@@ -15,7 +15,7 @@ describe('<Foo />', () => {
   it('calls componentDidMount', () => {
     spy(Foo.prototype, 'componentDidMount');
     const wrapper = mount(<Foo />);
-    expect(Foo.prototype.componentDidMount.calledOnce).to.be.true;
+    expect(Foo.prototype.componentDidMount.calledOnce).to.equal(true);
   });
 
   it('allows us to set props', () => {
@@ -31,7 +31,7 @@ describe('<Foo />', () => {
       <Foo onButtonClick={onButtonClick} />
     );
     wrapper.find('button').simulate('click');
-    expect(onButtonClick.calledOnce).to.be.true;
+    expect(onButtonClick.calledOnce).to.equal(true);
   });
 
 });

docs/api/shallow.md

@@ -24,7 +24,7 @@ describe('<MyComponent />', () => {
         <div className="unique" />
       </MyComponent>
     );
-    expect(wrapper.contains(<div className="unique" />)).to.be.true;
+    expect(wrapper.contains(<div className="unique" />)).to.equal(true);
   });
 
   it('simulates click events', () => {
@@ -33,7 +33,7 @@ describe('<MyComponent />', () => {
       <Foo onButtonClick={onButtonClick} />
     );
     wrapper.find('button').simulate('click');
-    expect(onButtonClick.calledOnce).to.be.true;
+    expect(onButtonClick.calledOnce).to.equal(true);
   });
 
 });

src/ReactWrapper.js

@@ -203,7 +203,7 @@ export default class ReactWrapper {
    * Example:
    * ```
    * const wrapper = mount(<MyComponent />);
-   * expect(wrapper.contains(<div className="foo bar" />)).to.be.true;
+   * expect(wrapper.contains(<div className="foo bar" />)).to.equal(true);
    * ```
    *
    * @param {ReactElement} node

src/ShallowWrapper.js

@@ -195,7 +195,7 @@ export default class ShallowWrapper {
    * Example:
    * ```
    * const wrapper = shallow(<MyComponent />);
-   * expect(wrapper.contains(<div className="foo bar" />)).to.be.true;
+   * expect(wrapper.contains(<div className="foo bar" />)).to.equal(true);
    * ```
    *
    * @param {ReactElement} node

src/__tests__/.eslintrc

@@ -1,7 +1,6 @@
 {
   "rules": {
     "padded-blocks": 0,
-    "no-unused-expressions": 0,
     "react/no-multi-comp": 0,
     "react/prop-types": 0,
     "react/no-did-mount-set-state": 0,