diff --git a/testdata/connection-string/valid-unix_socket-absolute.json b/testdata/connection-string/valid-unix_socket-absolute.json
index 5bb02476eb..66491db13b 100644
--- a/testdata/connection-string/valid-unix_socket-absolute.json
+++ b/testdata/connection-string/valid-unix_socket-absolute.json
@@ -30,6 +30,21 @@
       "auth": null,
       "options": null
     },
+    {
+      "description": "Unix domain socket (mixed case)",
+      "uri": "mongodb://%2Ftmp%2FMongoDB-27017.sock",
+      "valid": true,
+      "warning": false,
+      "hosts": [
+        {
+          "type": "unix",
+          "host": "/tmp/MongoDB-27017.sock",
+          "port": null
+        }
+      ],
+      "auth": null,
+      "options": null
+    },
     {
       "description": "Unix domain socket (absolute path with spaces in path)",
       "uri": "mongodb://%2Ftmp%2F %2Fmongodb-27017.sock",
diff --git a/testdata/connection-string/valid-unix_socket-absolute.yml b/testdata/connection-string/valid-unix_socket-absolute.yml
index 651e06fe39..cdfd00d332 100644
--- a/testdata/connection-string/valid-unix_socket-absolute.yml
+++ b/testdata/connection-string/valid-unix_socket-absolute.yml
@@ -23,6 +23,18 @@ tests:
                 port: ~
         auth: ~
         options: ~
+    -
+        description: "Unix domain socket (mixed case)"
+        uri: "mongodb://%2Ftmp%2FMongoDB-27017.sock"
+        valid: true
+        warning: false
+        hosts:
+            -
+                type: "unix"
+                host: "/tmp/MongoDB-27017.sock"
+                port: ~
+        auth: ~
+        options: ~
     -
         description: "Unix domain socket (absolute path with spaces in path)"
         uri: "mongodb://%2Ftmp%2F %2Fmongodb-27017.sock"
diff --git a/testdata/connection-string/valid-unix_socket-relative.json b/testdata/connection-string/valid-unix_socket-relative.json
index 2ce649ffc2..788720920b 100644
--- a/testdata/connection-string/valid-unix_socket-relative.json
+++ b/testdata/connection-string/valid-unix_socket-relative.json
@@ -30,6 +30,21 @@
       "auth": null,
       "options": null
     },
+    {
+      "description": "Unix domain socket (mixed case)",
+      "uri": "mongodb://rel%2FMongoDB-27017.sock",
+      "valid": true,
+      "warning": false,
+      "hosts": [
+        {
+          "type": "unix",
+          "host": "rel/MongoDB-27017.sock",
+          "port": null
+        }
+      ],
+      "auth": null,
+      "options": null
+    },
     {
       "description": "Unix domain socket (relative path with spaces)",
       "uri": "mongodb://rel%2F %2Fmongodb-27017.sock",
diff --git a/testdata/connection-string/valid-unix_socket-relative.yml b/testdata/connection-string/valid-unix_socket-relative.yml
index 7164188b3b..6d0d108205 100644
--- a/testdata/connection-string/valid-unix_socket-relative.yml
+++ b/testdata/connection-string/valid-unix_socket-relative.yml
@@ -23,6 +23,18 @@ tests:
                 port: ~
         auth: ~
         options: ~
+    -
+        description: "Unix domain socket (mixed case)"
+        uri: "mongodb://rel%2FMongoDB-27017.sock"
+        valid: true
+        warning: false
+        hosts:
+            -
+                type: "unix"
+                host: "rel/MongoDB-27017.sock"
+                port: ~
+        auth: ~
+        options: ~
     -
         description: "Unix domain socket (relative path with spaces)"
         uri: "mongodb://rel%2F %2Fmongodb-27017.sock"