Monkey-patch to add prototypes in describes to allow helper method overriding and mixins in specs

foo_spec.js

var MyMixin = {
  bar: function() {
    return "MyMixin bar";
  }
};

describe("First Level", function() {
  var variableFn = function() {
    return "First Level variableFn";
  };
  this.prototype.foo = function() {
    return "First Level foo";
  };
  jasmine.util.extend(this.prototype, MyMixin);

  beforeEach(function() {
    this.variable = variableFn();
    this.fooValue = this.foo();
    this.barValue = this.bar();
  });

  it("uses First Level variableFn", function() {
    expect(this.variable).toEqual("First Level variableFn"); // Fails!
    // The value is "Second Level variableFn";
  });

  it("uses First Level foo", function() {
    expect(this.fooValue).toEqual("First Level foo");
  });

  it("uses MyMixin bar", function() {
    expect(this.barValue).toEqual("MyMixin bar");
  });

  describe("Second Level", function() {
    variableFn = function() {
      return "Second Level variableFn";
    };
    this.prototype.foo = function() {
      return "Second Level foo";
    };

    it("uses Second Level variableFn", function() {
      expect(this.variable).toEqual("Second Level variableFn");
    });

    it("uses Second Level foo", function() {
      expect(this.fooValue).toEqual("Second Level foo");
    });
  });
});

jasmine-spec-prototype.js

(function() {
  var oldSuite = jasmine.Suite;
  jasmine.Suite = function() {
    oldSuite.apply(this, arguments);
    this.prototype = {};
  };
  jasmine.Suite.prototype = oldSuite.prototype;

  var addAttributes = function() {
    var specReservedAttributes = {};
    (function(specReservedAttributes) {
      for (var i in this) {
        if (this.hasOwnProperty(i)) {
          specReservedAttributes[i] = true;
        }
      }
    }).call(this, specReservedAttributes);

    var heirarchy = [];
    (function(heirarchy) {
      var currentSuite = this.suite;
      while (currentSuite) {
        heirarchy.unshift(currentSuite);
        currentSuite = currentSuite.parentSuite;
      }
    }).call(this, heirarchy);

    var prototypes = {};
    (function(prototypes) {
      for (var i=0; i < heirarchy.length; i++) {
        jasmine.util.extend(prototypes, heirarchy[i].prototype);
      }
      for (var i in prototypes) {
        if (prototypes.hasOwnProperty(i)) {
          if (specReservedAttributes[i]) {
            throw "Cannot override attribute " + i + " because it is used by jasmine";
          }
        }
      }
    }).call(this, prototypes);

    jasmine.util.extend(this, prototypes);
  };

  var addBeforesAndAftersToQueue = jasmine.Spec.prototype.addBeforesAndAftersToQueue;
  jasmine.Spec.prototype.addBeforesAndAftersToQueue = function() {
    addBeforesAndAftersToQueue.apply(this, arguments);
    this.queue.addBefore(new jasmine.Block(this.env, addAttributes, this));
  };
})();

purchase_flow_spec.js

describe("PurchaseFlow", function() {
  var event, purchaseFlow;
  this.prototype.newEvent = function() {
    return new Event({});
  };
  beforeEach(function() {
    event = this.newEvent();
    purchaseFlow = new PurchaseFlow({event: event});
  });

  it("shows the `#get_ticket` button", function() {

  });
  
  describe("`#get_ticket`.click", function() {
    describe("when the event is free", function() {
      this.prototype.newEvent = function() {
        return new Event({price_cents: 0});
      };

      it("creates a Ticket", function() {

      });
    });

    describe("when the event is not free", function() {
      this.prototype.newEvent = function() {
        return new Event({price_cents: 1000});
      };

      it("shows the payment options", function() {

      });
    });
  });
});