diff --git a/ocaml-lsp-server/test/e2e/__tests__/textDocument-diagnostics.ts b/ocaml-lsp-server/test/e2e/__tests__/textDocument-diagnostics.ts
index 5afa1a997..e68e81bf3 100644
--- a/ocaml-lsp-server/test/e2e/__tests__/textDocument-diagnostics.ts
+++ b/ocaml-lsp-server/test/e2e/__tests__/textDocument-diagnostics.ts
@@ -50,6 +50,24 @@ describe("textDocument/diagnostics", () => {
                     "line": 0,
                   },
                 },
+                "relatedInformation": Array [
+                  Object {
+                    "location": Object {
+                      "range": Object {
+                        "end": Object {
+                          "character": 4,
+                          "line": 0,
+                        },
+                        "start": Object {
+                          "character": 3,
+                          "line": 0,
+                        },
+                      },
+                      "uri": "file:///test.ml",
+                    },
+                    "message": "String literal begins here",
+                  },
+                ],
                 "severity": 1,
                 "source": "ocamllsp",
               },
@@ -165,9 +183,7 @@ describe("textDocument/diagnostics", () => {
           is not included in
             sig val x : unit end
           Values do not match: val x : int is not included in val x : unit
-          The type int is not compatible with the type unit
-          File \\"test.ml\\", line 2, characters 2-14: Expected declaration
-          File \\"test.ml\\", line 4, characters 6-7: Actual declaration",
+          The type int is not compatible with the type unit",
                 "range": Object {
                   "end": Object {
                     "character": 3,
@@ -178,6 +194,40 @@ describe("textDocument/diagnostics", () => {
                     "line": 2,
                   },
                 },
+                "relatedInformation": Array [
+                  Object {
+                    "location": Object {
+                      "range": Object {
+                        "end": Object {
+                          "character": 14,
+                          "line": 2,
+                        },
+                        "start": Object {
+                          "character": 2,
+                          "line": 2,
+                        },
+                      },
+                      "uri": "file:///test.ml",
+                    },
+                    "message": "Expected declaration",
+                  },
+                  Object {
+                    "location": Object {
+                      "range": Object {
+                        "end": Object {
+                          "character": 7,
+                          "line": 4,
+                        },
+                        "start": Object {
+                          "character": 6,
+                          "line": 4,
+                        },
+                      },
+                      "uri": "file:///test.ml",
+                    },
+                    "message": "Actual declaration",
+                  },
+                ],
                 "severity": 1,
                 "source": "ocamllsp",
               },
diff --git a/ocaml-lsp-server/test/e2e/src/LanguageServer.ts b/ocaml-lsp-server/test/e2e/src/LanguageServer.ts
index d522940a3..6179b6a77 100644
--- a/ocaml-lsp-server/test/e2e/src/LanguageServer.ts
+++ b/ocaml-lsp-server/test/e2e/src/LanguageServer.ts
@@ -63,7 +63,13 @@ export const startAndInitialize = async (
     processId: process.pid,
     rootUri: toURI(path.join(__dirname, "..")),
     workspaceFolders: [],
-    capabilities: {},
+    capabilities: {
+      textDocument: {
+        publishDiagnostics: {
+          relatedInformation: true,
+        },
+      },
+    },
     ...initializeParameters,
   };