Added common tests and change resize logic to use clientX and clientY for testability

Author: aeagle

@types/global.d.ts

@@ -0,0 +1,9 @@
+export {};
+
+declare global {
+	namespace jest {
+		interface Expect {
+			<T = any>(actual: T, message: String): Matchers<T>;
+		}
+	}
+}

jest.config.js

@@ -58,7 +58,13 @@ module.exports = {
 	// globalTeardown: undefined,
 
 	// A set of global variables that need to be available in all test environments
-	// globals: {},
+	globals: {
+		"ts-jest": {
+			tsConfig: {
+				target: "es2017",
+			},
+		},
+	},
 
 	// The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
 	// maxWorkers: "50%",
@@ -119,7 +125,7 @@ module.exports = {
 	// setupFiles: [],
 
 	// A list of paths to modules that run some code to configure or set up the testing framework before each test
-	// setupFilesAfterEnv: [],
+	setupFilesAfterEnv: ["jest-expect-message"],
 
 	// A list of paths to snapshot serializer modules Jest should use for snapshot testing
 	// snapshotSerializers: [],

package-lock.json

@@ -52,6 +52,7 @@
 		"babel-plugin-external-helpers": "^6.22.0",
 		"cssstyle": "^2.3.0",
 		"jest": "^25.4.0",
+		"jest-expect-message": "^1.0.2",
 		"node-sass": "^4.13.1",
 		"prettier": "^1.19.1",
 		"react": "^16.13.1",