Add pytests for plotCorrelation (salvage of #1370) (#1432)

* Added pytest for plotcorrelation

* Add missing file

* relaxed size tolerance

* Replace file size test with compare image

---------

Co-authored-by: Saim Momin <mominsaim12@gmail.com>

Author: adRn-s

pydeeptools/deeptools/test/test_data/multiBamSummary_result1.npz

@@ -0,0 +1,45 @@
+import deeptools.plotCorrelation as pc
+
+import os.path
+from os import unlink
+from matplotlib.testing.compare import compare_images
+
+
+ROOT = os.path.dirname(os.path.abspath(__file__)) + "/test_data/"
+COR_DATA_IN1 = ROOT + "multiBamSummary_result1.npz"
+COR_PLOT_1 = ROOT + "plotCorrelation_result1.png"
+COR_PLOT_2 = ROOT + "plotCorrelation_result2.png"
+
+
+def test_correlation_plot_with_minimal_options():
+    """
+    Test minimal command line args for correlation plot
+    with output as correlation matrix along with matrix
+    """
+    out_matrix = '/tmp/correlation_matrix.tsv'
+    out_png = '/tmp/correlation_plot1.png'
+    args = "--corData {} -p heatmap -c pearson -o {}  --outFileCorMatrix {}".format(COR_DATA_IN1, out_png, out_matrix).split()
+    pc.main(args)
+
+    _foo = open(out_matrix, "r")
+    resp = _foo.readlines()[2]
+    _foo.close()
+    expected = "'bowtie2 test1.bam'\t1.0000\t1.0000\n"
+    assert expected in resp, f"'{expected}' not found in '{resp}'"
+
+    res = compare_images(COR_PLOT_1, out_png, 50)
+    assert res is None, "Plots do not match"
+    unlink(out_png)
+
+
+def test_correlation_plot_scatter():
+    """
+    Test command line args for correlation plot with output as scatter plot
+    """
+    out_png2 = '/tmp/correlation_plot2.png'
+    args = "--corData {} -p scatterplot -c pearson  -o {}".format(COR_DATA_IN1, out_png2).split()
+    pc.main(args)
+
+    res = compare_images(COR_PLOT_2, out_png2, 50)
+    assert res is None, "Plots do not match"
+    unlink(out_png2)