diff --git a/addons/web/static/tests/helpers/mock_server.js b/addons/web/static/tests/helpers/mock_server.js
index a252863a3e9..e0575c7646e 100644
--- a/addons/web/static/tests/helpers/mock_server.js
+++ b/addons/web/static/tests/helpers/mock_server.js
@@ -499,9 +499,9 @@ export class MockServer {
     }
 
     _modifiersFromModel(node) {
-        const modifiersNames = ['invisible'];
-        if (['kanban', 'tree', 'form'].includes(node.tagName)) {
-            modifiersNames.push(...['readonly', 'required']);
+        const modifiersNames = ["invisible"];
+        if (["kanban", "tree", "form"].includes(node.tagName)) {
+            modifiersNames.push(...["readonly", "required"]);
         }
         return modifiersNames;
     }
@@ -1001,7 +1001,9 @@ export class MockServer {
             } else if (type === "datetime") {
                 const date = deserializeDateTime(val);
                 if (aggregateFunction === "hour") {
-                    return date.toFormat("HH:00 dd MMM");
+                    // The year is added to the format because is needed to correctly compute the
+                    // domain and the range (startDate and endDate).
+                    return date.toFormat("HH:00 dd MMM yyyy");
                 } else if (aggregateFunction === "day") {
                     return date.toFormat("yyyy-MM-dd");
                 } else if (aggregateFunction === "week") {
@@ -1093,12 +1095,11 @@ export class MockServer {
                         let startDate, endDate;
                         switch (dateRange) {
                             case "hour": {
-                                try {
-                                    startDate = parseDateTime(value, { format: "HH dd MMM" });
-                                } catch {
-                                    startDate = parseDateTime(value, { format: "HH:00 dd MMM" });
-                                }
+                                startDate = parseDateTime(value, { format: "HH:00 dd MMM yyyy" });
                                 endDate = startDate.plus({ hours: 1 });
+                                // Remove the year from the result value of the group. It was needed
+                                // to compute the startDate and endDate.
+                                group[gbField] = startDate.toFormat("HH:00 dd MMM");
                                 break;
                             }
                             case "day": {
diff --git a/addons/web/static/tests/mock_server_tests.js b/addons/web/static/tests/mock_server_tests.js
index f237b25f5b7..fe03bbfd39a 100644
--- a/addons/web/static/tests/mock_server_tests.js
+++ b/addons/web/static/tests/mock_server_tests.js
@@ -612,7 +612,7 @@ QUnit.module("MockServer", (hooks) => {
         );
     });
 
-    QUnit.skip("performRPC: read_group, group by datetime", async function (assert) {
+    QUnit.test("performRPC: read_group, group by datetime", async function (assert) {
         const server = new MockServer(data, {});
         let result = await server.performRPC("", {
             model: "bar",
@@ -685,35 +685,35 @@ QUnit.module("MockServer", (hooks) => {
             result.map((x) => x.__domain),
             [
                 [
-                    ["datetime", ">=", "2022-04-11 12:00:00"],
-                    ["datetime", "<", "2022-04-11 13:00:00"],
+                    ["datetime", ">=", "2016-04-11 12:00:00"],
+                    ["datetime", "<", "2016-04-11 13:00:00"],
                 ],
                 [
-                    ["datetime", ">=", "2022-10-26 12:00:00"],
-                    ["datetime", "<", "2022-10-26 13:00:00"],
+                    ["datetime", ">=", "2016-10-26 12:00:00"],
+                    ["datetime", "<", "2016-10-26 13:00:00"],
                 ],
                 [
-                    ["datetime", ">=", "2022-12-14 12:00:00"],
-                    ["datetime", "<", "2022-12-14 13:00:00"],
+                    ["datetime", ">=", "2016-12-14 12:00:00"],
+                    ["datetime", "<", "2016-12-14 13:00:00"],
                 ],
                 [
-                    ["datetime", ">=", "2022-12-15 12:00:00"],
-                    ["datetime", "<", "2022-12-15 13:00:00"],
+                    ["datetime", ">=", "2016-12-15 12:00:00"],
+                    ["datetime", "<", "2016-12-15 13:00:00"],
                 ],
                 [
-                    ["datetime", ">=", "2022-12-30 12:00:00"],
-                    ["datetime", "<", "2022-12-30 13:00:00"],
+                    ["datetime", ">=", "2019-12-30 12:00:00"],
+                    ["datetime", "<", "2019-12-30 13:00:00"],
                 ],
             ]
         );
         assert.deepEqual(
             result.map((x) => x.__range["datetime:hour"]),
             [
-                { from: "2022-04-11 12:00:00", to: "2022-04-11 13:00:00" },
-                { from: "2022-10-26 12:00:00", to: "2022-10-26 13:00:00" },
-                { from: "2022-12-14 12:00:00", to: "2022-12-14 13:00:00" },
-                { from: "2022-12-15 12:00:00", to: "2022-12-15 13:00:00" },
-                { from: "2022-12-30 12:00:00", to: "2022-12-30 13:00:00" },
+                { from: "2016-04-11 12:00:00", to: "2016-04-11 13:00:00" },
+                { from: "2016-10-26 12:00:00", to: "2016-10-26 13:00:00" },
+                { from: "2016-12-14 12:00:00", to: "2016-12-14 13:00:00" },
+                { from: "2016-12-15 12:00:00", to: "2016-12-15 13:00:00" },
+                { from: "2019-12-30 12:00:00", to: "2019-12-30 13:00:00" },
             ]
         );