Fix warnings raised by tests

[rouille]

Pull Request doc

Purpose

Fix warnings. There are three kinds of warnings

• one raised by pandas regarding the type of array used for indexing a data frame
• one raised by bokeh because we attempt to edit an empty legend
• one raised by matplotlib because too many figures have been opened

Closes #374.

What the code is doing

• Use a list in place of a set to index data frame in plot_scatter_capacity_vs_curtailment
• Use only coal generator to ensure glyphs are rendered on the map and legend is created in test_plot_capacity_map
• Close all plots in each test module where plots are generated

Testing

Warnings are not raised

Where to look

Changes are mostly done in the test modules

Usage Example/Visuals

N/A

Time estimate

5min

[jenhagg]

We can also use a fixture to close the plot automatically after each test (I wasn't sure so tried it out in this branch)

[BainanXia]

We can also use a fixture to close the plot automatically after each test (I wasn't sure so tried it out in this branch)

That's smart.

[rouille]

We can also use a fixture to close the plot automatically after each test (I wasn't sure so tried it out in this branch)

That's smart.

Much cleaner. I will cherry pick your commit and update the PR

[rouille]

We can also use a fixture to close the plot automatically after each test (I wasn't sure so tried it out in this branch)

That's smart.

Much cleaner. I will cherry pick your commit and update the PR

Done