diff --git a/04-findbugs/build.gradle b/04-findbugs/build.gradle
index 6423bdb..4f5b079 100644
--- a/04-findbugs/build.gradle
+++ b/04-findbugs/build.gradle
@@ -1,6 +1,8 @@
 apply plugin: 'java'
 apply plugin: 'pmd'
 apply plugin: 'checkstyle'
+
+// Documentation: http://www.gradle.org/docs/current/dsl/org.gradle.api.plugins.quality.FindBugsExtension.html
 apply plugin: 'findbugs'
 
 repositories {
diff --git a/16-stop-build/build.gradle b/16-stop-build/build.gradle
new file mode 100644
index 0000000..8df5d7e
--- /dev/null
+++ b/16-stop-build/build.gradle
@@ -0,0 +1,15 @@
+
+task workingTask {
+    description 'Task that works'
+    doLast {
+        println 'Everything is ok'
+    }
+}
+
+task failingTask {
+    description 'Task that fails'
+    doLast {
+        throw new GradleException("Problem detected. Build failed")
+    }
+}
+
diff --git a/17-testng-groovy/build.gradle b/17-testng-groovy/build.gradle
new file mode 100644
index 0000000..54e5987
--- /dev/null
+++ b/17-testng-groovy/build.gradle
@@ -0,0 +1,9 @@
+apply plugin: 'groovy'
+
+dependencies {
+    compile gradleApi()
+}
+
+test {
+    useTestNG()
+}
diff --git a/17-testng-groovy/src/main/groovy/com/ysoft/training/Calculator.groovy b/17-testng-groovy/src/main/groovy/com/ysoft/training/Calculator.groovy
new file mode 100644
index 0000000..a64f989
--- /dev/null
+++ b/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
+    }
+}
+
diff --git a/17-testng-groovy/src/test/groovy/com/ysoft/training/CalculatorTest.groovy b/17-testng-groovy/src/test/groovy/com/ysoft/training/CalculatorTest.groovy
new file mode 100644
index 0000000..e36835b
--- /dev/null
+++ b/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)
+    }
+}
+
diff --git a/16-debug-gradle-script/build.gradle b/18-debug-gradle-script/build.gradle
similarity index 100%
rename from 16-debug-gradle-script/build.gradle
rename to 18-debug-gradle-script/build.gradle
diff --git a/README.md b/README.md
index dcaa39e..ea5fdc5 100644
--- a/README.md
+++ b/README.md
@@ -164,7 +164,25 @@ Plugin is just counting lines in build.gradle file in current directory.
     gradle tasks
     gradle countLines
 
-## 16-debug-gradle-script
+## 16-stop-build
+
+It is possible to stop build by throwing exception.
+
+    gradle workingTask
+    gradle failingTask
+
+
+## 17-testng-groovy
+
+Example combines usage of TestNG for testing and tests written in Groovy.
+It is necessary to declare 'useTestNG()' in test configuration.
+Otherwise tests won't be executed.
+
+    gradle test
+
+Reports are stored in build/reports/tests/index.html
+
+## 18-debug-gradle-script
 
 Do not run in daemon mode.
 Set environment variable GRADLE_OPTS to
@@ -178,3 +196,4 @@ Start gradle task
 Attach remote debugger from Ide.
 
 More information: http://georgik.sinusgear.com/2014/06/23/how-to-debug-gradle-script/
+