test

filefinder/_filefinder.py

@@ -652,12 +652,30 @@ def search(self, **query):
         return type(self)(df)
 
     def concat(self, other):
-        """concatenate two FileContainers"""
+        """concatenate two FileContainers
+        
+        Parameters
+        ----------
+        other : FileContainer
+            The other FileContainer to concatenate.
+            
+        Returns
+        -------
+        FileContainer
+            The concatenated FileContainer.
+
+        Raises
+        ------
+        ValueError
+            If the other object is not a FileContainer.
+        ValueError
+            If the two FileContainers do not have the same keys.
+        """
 
         if not isinstance(other, FileContainer):
             raise ValueError("Can only concatenate two FileContainers.")
 
-        if not all(self.df.columns == other.df.columns):
+        if not self.df.columns is other.df.columns:
             raise ValueError("FileContainers must have the same keys.")
 
         ret = copy.copy(self)

filefinder/tests/test_filecontainer.py

@@ -1,3 +1,4 @@
+from numpy import diff
 import pandas as pd
 import pytest
 
@@ -140,6 +141,22 @@ def test_filecontainer_search(example_df, example_fc):
     pd.testing.assert_frame_equal(result.df, expected)
 
 
+def test_filecontainer_concat(example_fc):
+
+    with pytest.raises(ValueError, match="Can only concatenate two FileContainers."):
+        example_fc.concat("not a FileContainer")
+
+    with pytest.raises(ValueError, match="FileContainers must have the same keys"):
+        different_keys_fc = FileContainer(example_fc.df.loc[:, ["model", "scen"]])
+        example_fc.concat(different_keys_fc)
+
+    result = example_fc.concat(example_fc)
+    expected = pd.concat([example_fc.df, example_fc.df])
+
+    pd.testing.assert_frame_equal(result.df, expected)
+    assert result.__len__() == 10
+
+
 def test_fc_combine_by_key_deprecated(example_fc):
 
     with pytest.warns(FutureWarning, match="`combine_by_key` has been deprecated"):

filefinder/tests/test_filefinder.py

@@ -689,20 +689,3 @@ def test_find_unparsable():
         ValueError, match="Could not parse 'a_b/' with the pattern '{cat}_{cat}/'"
     ):
         ff.find_paths()
-
-
-def test_concat_FileContainers():
-
-        ff = FileFinder("{a}", "{b}", test_paths=["a/b", "c/d"])
-        result1 = ff.find_files()
-        result2 = ff.find_files()
-
-        result = result1.concat(result2)
-        expected = pd.concat([result1.df, result2.df])
-
-        pd.testing.assert_frame_equal(result.df, expected)
-
-        ff1 = FileFinder("{a}", "{c}", test_paths=["a/b", "c/d"])
-        result_diffkeys = ff1.find_files()
-
-