add example how to run TestNG test with Gradle on Groovy code

17-testng-groovy/build.gradle

@@ -0,0 +1,9 @@
+apply plugin: 'groovy'
+
+dependencies {
+    compile gradleApi()
+}
+
+test {
+    useTestNG()
+}

17-testng-groovy/src/main/groovy/com/ysoft/training/Calculator.groovy

@@ -0,0 +1,8 @@
+package com.ysoft.training
+
+class Calculator {
+    int add(x, y) {
+        return x+y
+    }
+}
+

17-testng-groovy/src/test/groovy/com/ysoft/training/CalculatorTest.groovy

@@ -0,0 +1,13 @@
+import com.ysoft.training.Calculator
+
+import org.testng.annotations.Test
+import org.testng.Assert
+
+class CalculatorTest {
+    @Test
+    void stitchInTimeSavesNine() {
+        def calculator = new Calculator()
+        Assert.assertEquals(calculator.add(4,5), 9)
+    }
+}
+