[Tests] Utils: add nodeHasType tests

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

@@ -6,6 +6,7 @@ import {
   nodeMatches,
   displayNameOfNode,
   spyMethod,
+  nodeHasType,
 } from 'enzyme/build/Utils';
 import {
   flatten,
@@ -614,4 +615,57 @@ describe('Utils', () => {
       expect(Object.getOwnPropertyDescriptor(obj, 'method')).to.deep.equal(descriptor);
     });
   });
+
+  describe('nodeHasType', () => {
+    it('is `false` if either argument is falsy', () => {
+      expect(nodeHasType(null, {})).to.equal(false);
+      expect(nodeHasType({}, null)).to.equal(false);
+    });
+
+    it('is `false` if `node` has a falsy `type`', () => {
+      expect(nodeHasType({}, {})).to.equal(false);
+      expect(nodeHasType({ type: null }, {})).to.equal(false);
+      expect(nodeHasType({ type: false }, {})).to.equal(false);
+      expect(nodeHasType({ type: '' }, {})).to.equal(false);
+      expect(nodeHasType({ type: 0 }, {})).to.equal(false);
+    });
+
+    it('compares `node.type` to `type` when `node.type` is a non-empty string', () => {
+      expect(nodeHasType({ type: 'foo' }, 'foo')).to.equal(true);
+      expect(nodeHasType({ type: 'foo' }, 'bar')).to.equal(false);
+    });
+
+    describe('when only `node.type.displayName` matches `type`', () => {
+      const x = {};
+      it('is `true` when `node.type` is an object', () => {
+        expect(nodeHasType(
+          { type: { displayName: x } },
+          x,
+        )).to.equal(true);
+      });
+
+      it('is `true` when `node.type` is a function', () => {
+        expect(nodeHasType(
+          { type: Object.assign(() => {}, { displayName: x }) },
+          x,
+        )).to.equal(true);
+      });
+    });
+
+    describe('when only `node.type.name` matches `type`', () => {
+      const x = {};
+      it('is `true` when `node.type` is an object', () => {
+        expect(nodeHasType(
+          { type: { name: x } },
+          x,
+        )).to.equal(true);
+      });
+
+      it('is `true` when `node.type` is a function', () => {
+        function namedType() {}
+
+        expect(nodeHasType({ type: namedType }, 'namedType')).to.equal(true);
+      });
+    });
+  });
 });