Add getter keys() tests

Author: hasier

instrumentation/opentelemetry-instrumentation-asgi/tests/test_getter.py

@@ -18,12 +18,18 @@
 
 
 class TestASGIGetter(TestCase):
-    def test_get_none(self):
+    def test_get_none_empty_carrier(self):
         getter = ASGIGetter()
         carrier = {}
         val = getter.get(carrier, "test")
         self.assertIsNone(val)
 
+    def test_get_none_empty_headers(self):
+        getter = ASGIGetter()
+        carrier = {"headers": []}
+        val = getter.get(carrier, "test")
+        self.assertIsNone(val)
+
     def test_get_(self):
         getter = ASGIGetter()
         carrier = {"headers": [(b"test-key", b"val")]}
@@ -44,7 +50,22 @@ def test_get_(self):
             "Should be case insensitive",
         )
 
-    def test_keys(self):
+    def test_keys_empty_carrier(self):
         getter = ASGIGetter()
         keys = getter.keys({})
         self.assertEqual(keys, [])
+
+    def test_keys_empty_headers(self):
+        getter = ASGIGetter()
+        keys = getter.keys({"headers": []})
+        self.assertEqual(keys, [])
+
+    def test_keys(self):
+        getter = ASGIGetter()
+        carrier = {"headers": [(b"test-key", b"val")]}
+        expected_val = ["test-key"]
+        self.assertEqual(
+            getter.keys(carrier),
+            expected_val,
+            "Should be equal",
+        )