TST: Test input matching

I still want to add more tests, but this should at least tentatively
close biocore#139.

tests/python/test_tools.py

@@ -5,6 +5,7 @@
 #
 # ----------------------------------------------------------------------------
 import unittest
+import pandas as pd
 from skbio import TreeNode
 from empress import Tree
 import empress.tools as tools
@@ -17,6 +18,28 @@ def mock_tree_from_nwk(self):
 
     def setUp(self):
         self.tree = self.mock_tree_from_nwk()
+        # Test table/metadata (mostly) adapted from Qurro:
+        # https://github.com/biocore/qurro/blob/b9613534b2125c2e7ee22e79fdff311812f4fefe/qurro/tests/test_df_utils.py#L178
+        self.table = pd.DataFrame(
+            {
+                "Sample1": [1, 2, 3, 4, 5, 6, 7, 8],
+                "Sample2": [8, 7, 6, 5, 4, 3, 2, 1],
+                "Sample3": [1, 0, 0, 0, 0, 0, 0, 0],
+                "Sample4": [0, 0, 0, 1, 0, 0, 0, 0]
+            },
+            index=["a", "c", "e", "d", "b", "x", "y", "z"]
+        )
+        self.sample_metadata = pd.DataFrame(
+            {
+                "Metadata1": [0, 0, 0, 1],
+                "Metadata2": [0, 0, 0, 0],
+                "Metadata3": [1, 2, 3, 4],
+                "Metadata4": ["abc", "def", "ghi", "jkl"]
+            },
+            index=list(self.table.columns)[:]
+        )
+        # TODO Also test matching feature metadata, when that's supported
+        self.feature_metadata = None
 
     def test_name_internal_nodes(self):
         t = Tree.from_tree(self.tree)
@@ -26,6 +49,30 @@ def test_name_internal_nodes(self):
         for i, node in enumerate(t.postorder()):
             self.assertEqual(node.name, names[i])
 
+    def test_match_inputs_basic(self):
+        """Tests the basic case where no samples are dropped, but some features
+           are present in the table but not the tree.
+        """
+        t = Tree.from_tree(self.tree)
+        tools.name_internal_nodes(t)
+        filtered_tbl, filtered_sample_metadata = tools.match_inputs(
+            t, self.table, self.sample_metadata
+        )
+        # No samples should've been dropped with this example data.
+        self.assertCountEqual(filtered_tbl.columns, self.table.columns)
+        self.assertCountEqual(
+            filtered_sample_metadata.index, self.sample_metadata.index
+        )
+        # Just for the sake of sanity, make sure we didn't accidentally drop
+        # any sample metadata columns
+        self.assertCountEqual(
+            filtered_sample_metadata.columns, self.sample_metadata.columns
+        )
+        # Some features should've been dropped from the table:
+        # "a", "b", "e", and "d" are the only features present in both the
+        # table and tree.
+        self.assertCountEqual(filtered_tbl.index, ["a", "b", "e", "d"])
+
 
 if __name__ == "__main__":
     unittest.main()