Adding TESTING.md (apache#2490)

README.md

@@ -113,6 +113,10 @@ Apache Geode includes the following features:
 See [BUILDING.md](https://github.com/apache/geode/blob/develop/BUILDING.md) for
 instructions on how to build the project.
 
+## <a name="testing"></a>Running Tests
+See [TESTING.md](https://github.com/apache/geode/blob/develop/TESTING.md) for
+instructions on how to run tests.
+
 ## <a name="started"></a>Geode in 5 minutes
 
 Geode requires installation of JDK version 1.8.  After installing Apache Geode,

TESTING.md

@@ -0,0 +1,38 @@
+# Running Tests
+
+## Prerequisites
+Before running tests, ensure all steps in the [BUILDING.md](https://github.com/apache/geode/blob/develop/BUILDING.md) have been performed.
+
+## Running Tests By Type
+Tests are broken up into five types - unit, integration, distributed, acceptance, and upgrade.  They can be executed using the following commands from the Geode repository root directory:
+* Unit tests: generally test a single class and run quickly  
+  `./gradlew test`
+* Integration tests: involve inter-operation of components or subsystems  
+  `./gradlew integrationTest`
+* Distributed tests: involve multiple members of a distributed system.  
+  `./gradlew distributedTest`
+* Acceptance tests: test Geode from end user perspective  
+  `./gradlew acceptanceTest`
+* Upgrade tests: test compatibility between versions of Geode and rolling upgrades  
+  `./gradlew upgradeTest`
+
+## Running Individual Tests
+To run an individual test, you can either
+1. Run the test in your [IDE](https://github.com/apache/geode/blob/develop/BUILDING.md#setting-up-intellij)
+2. Run the from terminal by specifying the sub-project and test type:  
+`./gradlew project:testType --tests testName`  
+For example:  
+    `./gradlew geode-core:test --tests ArrayUtilsTest`  
+    `./gradlew geode-core:distributedTest --tests ConnectionPoolDUnitTest`
+
+## Running Tests By Category
+To run a specific category of tests (eg: GfshTest):  
+`./gradlew project:testType -PtestCategory=fullyQualifiedTestClassName`  
+For example:  
+`./gradlew geode-core:distributedTest -PtestCategory=org.apache.geode.test.junit.categories.GfshTest`
+
+Available categories can be found in the `geode-junit/src/main/java/org/apache/geode/test/junit/categories` in the Geode repository.
+
+## Viewing Test Results
+Test results can be viewed by navigating to
+`build/reports/combined` in the Geode repository, then opening the `index.html` file in your browser.