diff --git a/jrnl/jrnl.py b/jrnl/jrnl.py
index e58cc956..f04dc471 100644
--- a/jrnl/jrnl.py
+++ b/jrnl/jrnl.py
@@ -51,10 +51,9 @@ def run(args):
 
     # Apply config overrides
     overrides = args.config_override
-    # TODO: substitute overriden KV pairs in config dict ONLY AFTER ADDING TESTS
-    for k in overrides:
-        logging.debug("Overriding %s from %s to %s" % (k, config[k], overrides[k]))
-        config[k] = overrides[k]
+    from .override import apply_overrides
+    config = apply_overrides(overrides,config)
+    
     # --- All the standalone commands are now done --- #
 
     # Get the journal we're going to be working with
diff --git a/jrnl/override.py b/jrnl/override.py
new file mode 100644
index 00000000..09de4258
--- /dev/null
+++ b/jrnl/override.py
@@ -0,0 +1,8 @@
+import logging 
+def apply_overrides(overrides: dict, base_config: dict) -> dict:
+    config = base_config.copy() 
+    for k in overrides:
+        logging.debug("Overriding %s from %s to %s" % (k, config[k], overrides[k]))
+        config[k] = overrides[k]
+
+    return config 
\ No newline at end of file
diff --git a/tests/test_override.py b/tests/test_override.py
new file mode 100644
index 00000000..25f38243
--- /dev/null
+++ b/tests/test_override.py
@@ -0,0 +1,27 @@
+import pytest
+
+import mock
+
+from jrnl.args import parse_args
+from jrnl.jrnl import run, search_mode
+from jrnl import install
+from jrnl.override import apply_overrides
+@pytest.fixture()
+def minimal_config(): 
+    cfg = { 
+        "colors":{ 
+            "body":"red",
+            "date":"green"
+        },
+        "default":"/tmp/journal.jrnl",
+        "editor":"vim"
+    }
+    yield cfg 
+
+def test_apply_override(minimal_config): 
+    config = minimal_config.copy()
+    overrides = {
+        'editor':'nano'
+    }
+    config = apply_overrides(overrides, config)
+    assert config['editor']=='nano'
\ No newline at end of file