Edit in JSFiddle

describe('toBeTruthy', function() {
    it('passes if subject is true', function() {
        expect(true).toBeTruthy();
        expect(false).not.toBeTruthy();
    });
    
    it('passes if subject is a non empty string', function() {
        expect('Should pass').toBeTruthy();        
    });
    
    it('passes if subject is a number not equal 0', function() {
        expect(1).toBeTruthy();        
    });

    it('fails if subject is an empty string', function() {
        expect('').not.toBeTruthy();
    });

    it('fails if subject is false', function() {
        expect(false).not.toBeTruthy();
    });
    
    it('fails if subject is 0', function() {
        expect(0).not.toBeTruthy();
    });
});

execJasmine();