diff --git a/test/resolvers/QueryResolverTests.test.ts b/test/resolvers/QueryResolverTests.test.ts
index 3da3015..c806a9e 100644
--- a/test/resolvers/QueryResolverTests.test.ts
+++ b/test/resolvers/QueryResolverTests.test.ts
@@ -24,12 +24,17 @@ describe("QueryResolvers", () => {
     repository = new UnoptimizedInMemoryRepository();
   });
 
+  async function addMockSystems() {
+    const systems = generateMockSystems();
+    await Promise.all(systems.map(async (system) => {
+      await repository.addOrUpdateSystem(system);
+    }));
+    return systems;
+  }
+
   describe("systems", () => {
     it("returns systems from the repository", async () => {
-      const systems = generateMockSystems();
-      await Promise.all(systems.map(async (system) => {
-        await repository.addOrUpdateSystem(system);
-      }));
+      const systems = await addMockSystems();
 
       const query = `
       query GetSystems
@@ -38,7 +43,7 @@ describe("QueryResolvers", () => {
           name
         }
       }
-      `
+      `;
 
       const response = await testServer.executeOperation({
         query,
@@ -55,16 +60,50 @@ describe("QueryResolvers", () => {
   });
 
   describe("system", () => {
+    const query = `
+    query GetSystem($id: ID!)
+    {
+      system(id: $id) {
+        name
+      }
+    }
+    `;
+
     it("returns a system for an ID from the repository", async () => {
+      const systems = await addMockSystems();
+      const systemToGet = systems[1];
 
-    });
-
-    it("returns null if no id provided", async () => {
+      const response = await testServer.executeOperation({
+        query,
+        variables: {
+          id: systemToGet.id,
+        }
+      }, {
+        contextValue: {
+          repository,
+        }
+      });
 
+      assert(response.body.kind === "single");
+      expect(response.body.singleResult.errors).toBeUndefined();
+      expect(response.body.singleResult.data?.system).toBeDefined();
     });
 
     it("returns null if there is no system", async () => {
+      const response = await testServer.executeOperation({
+        query,
+        variables: {
+          id: "nonexistent-id",
+        }
+      }, {
+        contextValue: {
+          repository,
+        }
+      });
 
+      assert(response.body.kind === "single");
+      expect(response.body.singleResult.errors).toBeUndefined();
+      expect(response.body.singleResult.data?.system).toBeNull();
     });
   });
 });