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// Code under test
var MyApp = function () {

    var isValid = function (scaleMin, scaleMax) {
        if (scaleMin === 0 && scaleMax === 0) {
            return true;
        }
        
        if (scaleMax <= scaleMin) {
            return "Scale max must be greater than Scale min.";
        }

        return true;
    };
    
    return {
        isValid: isValid
    };
};

// Specs
describe("isValid", function () {

    var myApp = new MyApp();
    
    it("Should be valid when scale min/max are both 0", function () {
        var scaleMin = 0,
            scaleMax = 0;

        expect(myApp.isValid(scaleMin, scaleMax)).toBe(true);
    });

    it("Should be valid when scale min is less than scaleMax", function () {
        var scaleMin = 0,
            scaleMax = 1;

        expect(myApp.isValid(scaleMin, scaleMax)).toBe(true);
    });

    it("Should be invalid when scale min is equal to scaleMax", function () {
        var scaleMin = 1,
            scaleMax = 1;

        expect(myApp.isValid(scaleMin, scaleMax)).toBe("Scale max must be greater than Scale min.");
    });

    it("Should be invalid when scale min is greater than scaleMax", function () {
        var scaleMin = 1,
            scaleMax = 0;

        expect(myApp.isValid(scaleMin, scaleMax)).toBe("Scale max must be greater than Scale min.");
    });

});