diff --git a/back/src/Services/MapFetcher.ts b/back/src/Services/MapFetcher.ts
index 99465ac4..0a8cb4bd 100644
--- a/back/src/Services/MapFetcher.ts
+++ b/back/src/Services/MapFetcher.ts
@@ -36,8 +36,10 @@ class MapFetcher {
     /**
      * Returns true if the domain name is localhost of *.localhost
      * Returns true if the domain name resolves to an IP address that is "private" (like 10.x.x.x or 192.168.x.x)
+     *
+     * @private
      */
-    private async isLocalUrl(url: string): Promise<boolean> {
+    async isLocalUrl(url: string): Promise<boolean> {
         const urlObj = new URL(url);
         if (urlObj.hostname === "localhost" || urlObj.hostname.endsWith(".localhost")) {
             return true;
@@ -46,7 +48,7 @@ class MapFetcher {
         let addresses = [];
         if (!ipaddr.isValid(urlObj.hostname)) {
             const resolver = new Resolver();
-            addresses = await promisify(resolver.resolve)(urlObj.hostname);
+            addresses = await promisify(resolver.resolve).bind(resolver)(urlObj.hostname);
         } else {
             addresses = [urlObj.hostname];
         }
diff --git a/back/tests/MapFetcherTest.ts b/back/tests/MapFetcherTest.ts
new file mode 100644
index 00000000..3b47e73b
--- /dev/null
+++ b/back/tests/MapFetcherTest.ts
@@ -0,0 +1,26 @@
+import { arrayIntersect } from "../src/Services/ArrayHelper";
+import { mapFetcher } from "../src/Services/MapFetcher";
+
+describe("MapFetcher", () => {
+    it("should return true on localhost ending URLs", async () => {
+        expect(await mapFetcher.isLocalUrl("https://localhost")).toBeTrue();
+        expect(await mapFetcher.isLocalUrl("https://foo.localhost")).toBeTrue();
+    });
+
+    it("should return true on DNS resolving to a local domain", async () => {
+        expect(await mapFetcher.isLocalUrl("https://127.0.0.1.nip.io")).toBeTrue();
+    });
+
+    it("should return true on an IP resolving to a local domain", async () => {
+        expect(await mapFetcher.isLocalUrl("https://127.0.0.1")).toBeTrue();
+        expect(await mapFetcher.isLocalUrl("https://192.168.0.1")).toBeTrue();
+    });
+
+    it("should return false on an IP resolving to a global domain", async () => {
+        expect(await mapFetcher.isLocalUrl("https://51.12.42.42")).toBeFalse();
+    });
+
+    it("should return false on an DNS resolving to a global domain", async () => {
+        expect(await mapFetcher.isLocalUrl("https://maps.workadventu.re")).toBeFalse();
+    });
+});