fix(conformance-tests): Fix event handler tests (#98)

* fix tests for events, introduce tests for handlers

* remove unnecessary import

* rename 'wrappedComponent' to 'component'

Author: kuzhelov

test/specs/commonTests/isConformant.tsx

@@ -253,9 +253,6 @@ export default (Component, options: any = {}) => {
         // onKeyDown => keyDown
         const eventName = _.camelCase(listenerName.replace('on', ''))
 
-        // onKeyDown => handleKeyDown
-        const handlerName = _.camelCase(listenerName.replace('on', 'handle'))
-
         const handlerSpy = jest.fn()
         const props = {
           ...requiredProps,
@@ -286,6 +283,11 @@ export default (Component, options: any = {}) => {
         if (customHandler) {
           customHandler(eventShape)
         } else {
+          if (Component.propTypes[listenerName]) {
+            throw new Error(
+              `Handler for '${listenerName}' is not passed to child event emitter element <${eventTarget.type()} />`,
+            )
+          }
           return
         }
 
@@ -298,6 +300,9 @@ export default (Component, options: any = {}) => {
         //                   ^ was not called once on "blur"
         const leftPad = ' '.repeat(info.displayName.length + listenerName.length + 3)
 
+        // onKeyDown => handleKeyDown
+        const handlerName = _.camelCase(listenerName.replace('on', 'handle'))
+
         try {
           expect(handlerSpy).toHaveBeenCalled()
         } catch (err) {
@@ -313,7 +318,10 @@ export default (Component, options: any = {}) => {
 
         if (_.has(Component.propTypes, listenerName)) {
           expectedArgs = [eventShape, component.props()]
-          errorMessage = 'was not called with (event, data)'
+          errorMessage =
+            'was not called with (event, data).\n' +
+            `Ensure that 'props' object is passed to '${listenerName}'\n` +
+            `event handler of <${Component.displayName} />.`
         }
 
         // Components should return the event first, then any data
@@ -438,4 +446,37 @@ export default (Component, options: any = {}) => {
       expect(Component.displayName).toEqual(info.constructorName)
     })
   })
+
+  const validListenerNames = _.reduce(
+    syntheticEvent.types,
+    (result, { listeners }) => [...result, ...listeners],
+    [],
+  )
+
+  // ---------------------------------------
+  // Opt-in tests
+  // ---------------------------------------
+  return {
+    // -------------------------------------
+    // Ensure that props are passed as a
+    // second argument to event handler
+    // -------------------------------------
+    hasExtendedHandlerFor(onEventName) {
+      describe(`has extended handler for '${onEventName}' event`, () => {
+        test(`'${onEventName}' is a valid event listener name`, () => {
+          expect(validListenerNames).toContain(onEventName)
+        })
+
+        test(`is declared in props`, () => {
+          expect(Component.propTypes[onEventName]).toBeTruthy()
+        })
+      })
+
+      // -----------------------------------
+      // Allows chained calls for optional
+      // test suites
+      // -----------------------------------
+      return this
+    },
+  }
 }