diff --git a/README.md b/README.md
index c0e198e..5f20926 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ from .parser import parse_file, parse_folder  # noqa: F401
    Splits a data frame based on the unique values of a column. Will return a 
    dict, with the unique values as keys and the corresponding data frame as 
    value
- - **apply_map(data_frame, map, idex_col)**
+ - **apply_map(data_frame, map, index_col)**
    Adds information provided in the nested dictionary `map` to a data frame, 
    based on the values in the data_frame column `index_col`. 
  - **apply_exposure_map(data_frame, exposure_map)**
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 517b77c..5913376 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -195,3 +195,44 @@ def test_apply_map(exposure_df):
         partial = result.loc[mask]
         assert set(partial["SomeColumn"].unique()) == {value["SomeColumn"]}
         assert set(partial["OtherColumn"].unique()) == {value["OtherColumn"]}
+
+
+def test_apply_map_keys_not_in_df(exposure_df):
+    from sensospot_data.utils import apply_map
+
+    map = {
+        1: {"some_col": "A", "other_col": 9},
+        2: {"some_col": "B", "other_col": 8},
+        3: {"some_col": "C", "other_col": 7},
+        4: {"some_col": "D", "other_col": 6},
+    }
+
+    result = apply_map(exposure_df, map, "Exposure.Id")
+
+    for key in (1, 2, 3):
+        value = map[key]
+        mask = result["Exposure.Id"] == key
+        partial = result.loc[mask]
+        assert set(partial["some_col"].unique()) == {value["some_col"]}
+        assert set(partial["other_col"].unique()) == {value["other_col"]}
+
+    assert "D" not in set(result["some_col"].unique())
+    assert "6" not in set(result["other_col"].unique())
+
+
+def test_apply_map_not_all_keys_map_to_df(exposure_df):
+    from sensospot_data.utils import apply_map
+
+    map = {
+        1: {"some_col": "A", "other_col": 9},
+        3: {"some_col": "C", "other_col": 7},
+    }
+
+    result = apply_map(exposure_df, map, "Exposure.Id")
+
+    assert not result.iloc[0].hasnans
+    assert result.iloc[1].hasnans
+    assert not result.iloc[2].hasnans
+
+    assert result["some_col"].hasnans
+    assert result["other_col"].hasnans