add kegg enrichment function tests

tests/test_anoexpress.py

@@ -104,4 +104,22 @@ def test_plot_gene_expression_type(plot_type):
         analysis="gamb_colu", 
         microarray=False, 
         plot_type=plot_type,
-        )
+        )
+
+def test_go_hypergeometric():
+    go = xpress.go_hypergeometric(analysis='gamb_colu_arab_fun', name="median", func=np.nanmedian
+        )
+    assert isinstance(go, pd.DataFrame)
+    assert go.iloc[0,0] == 'GO:0042302' # check first value is correct
+
+def test_pfam_hypergeometric():
+    pfam = xpress.pfam_hypergeometric(analysis='gamb_colu_arab_fun', name="median", func=np.nanmedian
+        )
+    assert isinstance(pfam, pd.DataFrame)
+    assert pfam.iloc[0,0] == 'C_tripleX' # check first value is correct
+
+def test_kegg_hypergeometric():
+    kegg = xpress.kegg_hypergeometric(analysis='gamb_colu_arab_fun', name="median", func=np.nanmedian
+        )
+    assert isinstance(kegg, pd.DataFrame)
+    assert kegg.iloc[0,0] == 'aga00982' # check first value is correct