Unit Testing JavaScript with Jasmine

The lack of good unit tests integrated with Maven was one of the things that kept me away from serious JavaScript development. So recently, I tried out Jasmine for unit testing JavaScript code. This is pretty cool stuff.

Add this snippet to pom.xml:

  <build>
    <plugins>
      <plugin>
        <groupid>com.github.searls</groupid>
        <artifactid>jasmine-maven-plugin</artifactid>
        <version>1.1.0</version>
        <executions>
          <execution>
            <goals>
              <goal>test</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          
        </configuration>
      </plugin>
    </plugins>
  </build>

Then I can write a unit test specification like this:

describe("LinearMemory64K", function() {
    var memory;
    
    beforeEach(function() {
        memory = new LinearMemory64K();
    });
    
    it("can be read", function() {
        var data = memory.read(0x8000);
        expect(data).toEqual(0x00);
    });
    
    it("can be written to", function() {
        memory.write(0x8000, 0xEA);
        var data = memory.read(0x8000);
        expect(data).toEqual(0xEA);
    });
    
    it("has 16 address lines", function() {
        memory.write(0x18000, 0xEA);
        var data = memory.read(0x8000);
        expect(data).toEqual(0xEA);
    });


    it("has 8 data lines", function() {
        memory.write(0x8000, 0x1EA);
        var data = memory.read(0x8000);
        expect(data).toEqual(0xEA);
    });
    
    it("handles negative numbers", function() {
        memory.write(0x8000, -1);
        var data = memory.read(0x8000);
        expect(data).toEqual(0xFF);
    });


    it("uses two's compliment to represent negative numbers", function() {
        memory.write(0x8000, -2);
        var data = memory.read(0x8000);
        expect(data).toEqual(0xFE);
    });
});

In my example, I've used the toEqual() matcher, but the Jasmine Matcher API offers a lot more. I'm looking forward to writing a lot more JavaScript code in the future.