Test simulations

[nateosher]

This primarily consists of tests for the simulation functions; I had to tweak a couple of things to be consistent with the tests too though. Nothing crazy.

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +2.54 :tada:

Comparison is base (61475e9) 51.70% compared to head (fb43fa7) 54.25%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #30 +/- ## ========================================== + Coverage 51.70% 54.25% +2.54% ========================================== Files 31 33 +2 Lines 673 741 +68 ========================================== + Hits 348 402 +54 - Misses 325 339 +14 ``` | [Impacted Files](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) | Coverage Δ | | |---|---|---| | [R/GridRect.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9HcmlkUmVjdC5S) | `100.00% <100.00%> (+100.00%)` | :arrow_up: | | [R/SimulateGrid.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9TaW11bGF0ZUdyaWQuUg==) | `100.00% <100.00%> (+100.00%)` | :arrow_up: | | [R/patient\_boxplots.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9wYXRpZW50X2JveHBsb3RzLlI=) | `0.00% <0.00%> (ø)` | | | [R/plot\_pairwise\_group\_heatmap.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9wbG90X3BhaXJ3aXNlX2dyb3VwX2hlYXRtYXAuUg==) | `0.00% <0.00%> (ø)` | | | [R/plot\_qdist.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9wbG90X3FkaXN0LlI=) | `0.00% <0.00%> (ø)` | | | [R/plot\_quantile\_mask.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9wbG90X3F1YW50aWxlX21hc2suUg==) | `0.00% <0.00%> (ø)` | | | [R/MltplxExperiment.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9NbHRwbHhFeHBlcmltZW50LlI=) | `86.41% <0.00%> (+0.16%)` | :arrow_up: | | [R/GridCircle.R](https://codecov.io/gh/nateosher/DistDist/pull/30?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-Ui9HcmlkQ2lyY2xlLlI=) | `100.00% <0.00%> (+100.00%)` | :arrow_up: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None)

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[mariamasotti1]

@nateosher Ive been playing with this code more and I noticed that SimulateGrid() spits an error if no points are simulated for a cell type (like if the intensity is particularly low). Could you change it so it still produces a ppp object just with no points of that type?

[nateosher]

Thanks for the heads up- should be an easy enough fix