DRIVERS-1400: Add test to ensure read preference tags are case sensitive (#1693)

Author: alcaeus

source/uri-options/tests/read-preference-options.json

@@ -26,6 +26,17 @@ tests:
             readPreferenceTags:
                 -
                     dc: "ny"
+    -
+        description: "Read preference tags are case sensitive"
+        uri: "mongodb://example.com/?readPreference=secondary&readPreferenceTags=dc:NY"
+        valid: true
+        warning: false
+        hosts: ~
+        auth: ~
+        options:
+            readPreferenceTags:
+                -
+                    dc: "NY"
     -
         description: "Invalid readPreferenceTags causes a warning"
         uri: "mongodb://example.com/?readPreferenceTags=invalid"