Merge pull request #51 from todvora/tests-readme-update

Java wrapper description in tests readme

test/README.markdown

@@ -13,6 +13,42 @@ Main indicator of tests result is [exit code](http://tldp.org/LDP/abs/html/exit-
 In case of everything went well, return code is `0`. In case of tests fail, exit code is set to nonzero. Exit code is monitored by Travis-CI and informs about tests success or fail.
 Tests produce verbose log messages for detecting problems and errors.
 
+## Java wrapper
+The bridge between JUnit tests and Variety written in pure JS is [Java wrapper for variety](https://github.com/variety/variety/blob/master/test/src/main/java/com/github/variety/Variety.java).
+Currently the wrapper is optimized for tests usage and allows:
+
+- Specify analyzed DB and collection name
+- Forward all config parameters to Variety.js
+- execute mongo shell with all the config values and path to Variety
+- Collect standard output of mongo shell
+- Verify results values (assertion)
+- Access mongo database through native java driver (initialization, cleanup)
+
+Wrapper can be created with this command:
+
+```
+Variety wrapper = new Variety("test", "users");
+```
+
+Where the first parameter is analyzed database name and second analyzed collection name. Wrapper is written following
+[builder pattern](https://en.wikipedia.org/wiki/Builder_pattern):
+
+```
+VarietyAnalysis analysis = new Variety("test", "users")
+                .withMaxDepth(10)
+                .withSort("{name:-1}")
+                .withLimit(5)
+                .runAnalysis();
+```
+
+```VarietyAnalysis``` is the actual analysis result. Main purpose is to easy verify results:
+
+```
+verifyResult(String key, double totalOccurrences, double percentContaining, String... types)
+```
+If the result does not match expectations, AssertionError is thrown (standard JUnit behavior).
+
+
 ## Tests lifecycle
  - Initialization, prepare data. Every test has method annotated with `@Before`.
  - Variety analysis, run variety.js against prepared data and verify results. See `Variety.java`, method `runAnalysis()` and methods annotated with `@Test`.