diff --git a/tests/tests_unit/test_input_handling.py b/tests/tests_unit/test_input_handling.py
index 03d9c26..0b8da9c 100644
--- a/tests/tests_unit/test_input_handling.py
+++ b/tests/tests_unit/test_input_handling.py
@@ -14,6 +14,7 @@ def test_handle_input_rates_works_with_full_correct_inputs():
         end_date=datetime.datetime.now() - datetime.timedelta(days=1),
         currencies="USD,EUR,GBP",
         dry_run=False,
+        rates_source="mock",
         ignore_warnings=True,
         output="test_output.csv",
     )
@@ -24,6 +25,7 @@ def test_handle_input_rates_works_with_full_correct_inputs():
         ),
         "currencies": {Currency("USD"), Currency("EUR"), Currency("GBP")},
         "dry_run": False,
+        "rates_source": "mock",
         "ignore_warnings": True,
         "output": pathlib.Path("test_output.csv"),
     }
@@ -40,6 +42,20 @@ def test_handle_input_rates_raises_with_bad_currency_code():
             end_date=datetime.datetime.now() + datetime.timedelta(days=7),
             currencies="not_a_currency,USD,not_this_either",
             dry_run=False,
+            rates_source="mock",
+            ignore_warnings=True,
+            output="test_output.csv",
+        )
+
+
+def test_handle_input_rates_raises_with_invalid_rates_source():
+    with pytest.raises(ValueError):
+        handle_get_rates_inputs(
+            start_date=datetime.datetime.now(),
+            end_date=datetime.datetime.now() + datetime.timedelta(days=7),
+            currencies="not_a_currency,USD,not_this_either",
+            dry_run=False,
+            rates_source="clearly not a rates source. I guess, dunno.",
             ignore_warnings=True,
             output="test_output.csv",
         )
@@ -52,6 +68,7 @@ def test_handle_input_rates_raises_with_start_date_after_end_date():
             end_date=datetime.datetime.now() - datetime.timedelta(days=7),
             currencies="GBP,USD",
             dry_run=False,
+            rates_source="mock",
             ignore_warnings=True,
             output="test_output.csv",
         )
@@ -64,6 +81,7 @@ def test_handle_input_rates_raises_with_output_different_than_csv():
             end_date=datetime.datetime.now() + datetime.timedelta(days=7),
             currencies="GBP,USD",
             dry_run=False,
+            rates_source="mock",
             ignore_warnings=True,
             output="test_output.xlsx",
         )
@@ -75,6 +93,7 @@ def test_handle_input_rates_brings_future_end_date_to_today():
         end_date=datetime.datetime.now() + datetime.timedelta(days=7),
         currencies="USD,EUR,GBP",
         dry_run=False,
+        rates_source="mock",
         ignore_warnings=True,
         output="test_output.csv",
     )
@@ -88,6 +107,7 @@ def test_handle_input_rates_start_and_end_date_equal_works_fine():
         end_date=datetime.datetime.now(),
         currencies="USD,EUR,GBP",
         dry_run=False,
+        rates_source="mock",
         ignore_warnings=True,
         output="test_output.csv",
     )
@@ -98,6 +118,7 @@ def test_handle_input_rates_start_and_end_date_equal_works_fine():
         ),
         "currencies": {Currency("USD"), Currency("EUR"), Currency("GBP")},
         "dry_run": False,
+        "rates_source": "mock",
         "ignore_warnings": True,
         "output": pathlib.Path("test_output.csv"),
     }
diff --git a/xexe/cli.py b/xexe/cli.py
index 5403cb4..dbed5d8 100644
--- a/xexe/cli.py
+++ b/xexe/cli.py
@@ -74,7 +74,7 @@ def get_rates(
     end_date: Union[str, datetime.datetime, datetime.date],
     currencies: Union[None, str],
     dry_run: bool,
-    rates_sources: str,
+    rates_source: str,
     ignore_warnings: bool,
     output: pathlib.Path,
 ):
@@ -83,7 +83,7 @@ def get_rates(
         end_date=end_date,
         currencies=currencies,
         dry_run=dry_run,
-        rates_sources=rates_sources,
+        rates_source=rates_source,
         ignore_warnings=ignore_warnings,
         output=output,
     )
diff --git a/xexe/processes.py b/xexe/processes.py
index bcb58a2..a6b5375 100644
--- a/xexe/processes.py
+++ b/xexe/processes.py
@@ -56,6 +56,7 @@ def run_get_rates(
     date_range: DateRange,
     currencies: List[Currency],
     dry_run: bool,
+    rates_source: str,
     ignore_warnings: bool,
     output: pathlib.Path,
 ) -> None: