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+Project: /_project.yaml
+Book: /_book.yaml
+
+{% include "_versions.html" %}
+
+<!--
+  Copyright 2018 The Android Open Source Project
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+# JAR (Java) Host Tests
+
+JAR host tests should be implemented to provide complete code coverage of your
+software. Follow the instructions to [Build local unit
+tests](https://developer.android.com/training/testing/unit-testing/local-unit-tests){: .external}.
+Write small unit tests to validate a specific function and nothing more.
+
+## Example
+
+The following Blueprint file provides a simple Hello World JAR host test example to
+copy and adapt to your needs:
+[platform_testing/tests/example/jarhosttest/Android.bp](https://android.googlesource.com/platform/platform_testing/+/master/tests/example/jarhosttest/Android.bp)
+
+This corresponds to the actual test code found at:
+[platform_testing/tests/example/jarhosttest/test/android/test/example/helloworld/HelloWorldTest.java](platform_testing/+/master/tests/example/jarhosttest/test/android/test/example/helloworld/HelloWorldTest.java)
+
+A snapshot of the Blueprint file is included here for convenience:
+
+   ```
+   java_test_host {
+    name: "HelloWorldHostTest",
+
+    test_suites: ["general-tests"],
+
+    srcs: ["test/**/*.java"],
+
+    static_libs: [
+        "junit",
+        "mockito",
+    ],
+}
+   ```
+
+Note the `java_host_test` declaration at the beginning indicates this is a JAR
+host test.
+
+## Settings
+
+The following settings garner explanation:
+
+   ```
+    name: "HelloWorldHostTest",
+   ```
+
+
+The `name` setting is required when the `java_test_host` module type is specified
+(at the start of the block). It gives a name to your module, and the resulting
+JAR will be named the same and with a `.jar` suffix, e.g. in this case, the
+resulting test JAR is named as `HelloWorldHostTest.jar`.  In addition, this also
+defines a make target name for your module, so that you can use `make [options]
+<HelloWorldHostTest>` to build your test module and all its dependencies.
+
+
+```
+    test_suites: ["general-tests"],
+```
+
+The `test_suites` setting makes the test easily discoverable by the Trade
+Federation test harness. Other suites can be added here such as CTS so that this
+test may be shared.
+
+   ```
+    static_libs: [
+        "junit",
+    ],
+   ```
+
+The `static_libs` setting instructs the build system to incorporate the contents
+of the named modules into the resulting apk of current module. This means that
+each named module is expected to produce a `.jar` file, and its content will be
+used for resolving classpath references during compile time, as well as
+incorporated into the resulting apk.