doc: Update readme

README.md

@@ -3,10 +3,19 @@
 _python-jvm-interpreter_ is an implementation of the Java Virtual Machine in
 Python. It works by parsing and interpreting the Java Class files.
 
+## Dependencies
+In order to compile Java code to Java Bytecode, you will need to have
+`javac`. If you just want to run bytecode that is already compiled, all you need
+is a Python interpreter.
+
 ## Running the tests
-In order to run the examples or unit tests, you need to compile the Java source
-files into _.class_ files. To do this, you can use `javac`. In order to compile
-all the files in the example folder, you can run `javac *.java`.
+The project comes with a number of unit tests. If you run the shell script
+`test.sh`, it will compile the Java files in the example directory and run the
+unit tests. You will be able to see how many test passed and how many failed.
+
+Even if you haven't touched anything critical, it is always a good idea to run
+the unit tests after each change. This will make sure that nothing breaks, and
+if it does you will immediately know why it broke.
 
 As more functionality is implemented, the amount of test cases should be
-increased in order to make it easier to check if anything is broken.
+increased in order to make it easier to check if anything is broken.