some-controller.js

$modal.open({
  resolve: {
    value: function() {
      return _this.value;
    }
  }
});

some-controller.spec.js

describe('$modal.open()', function() {
  it('should resolve the value', function() {
    var valueTester = {
      asymmetricMatch: function(value) {
        return value() === controller.value;
      }
    };

    expect($modal.open)
      .toHaveBeenCalledWith(jasmine.objectContaining({
        resolve: {value: valueTester}
      }));
  });
});