d3.chart [unit testing]: Spying on Chart Methods

[E Dana]

What is the best way to spy on a d3.chart method that is called during `initialize()`?

Context:

• d3.chart library
• Unit testing with mocha and sinon

The below code requires instantiating the grid twice:

Once to create the Grid instance on which the spy is created

Then a second time for the spied method to be recorded

The below code works, but I wonder if there is a better and cleaner way. 

*Code is based on the unit tests for d3.chart itself.

test("Calls `util.parse.options` with `options`", function() {

var gridSpy = this.gridSpy =

d3.select("#test").chart("Grid");

sinon.spy(gridSpy.deep.nested, "method");

this.grid = d3.select('#test')

.append('svg')

.chart(

'Grid', 

{ options: this.options }

);

assert.deepEqual(gridSpy.deep.nested.method.args[0][0], this.options);

});

Thanks,

-Evan