messages: Add tests for transform_content.

This commit introduces tests for the `transform_content` class method,
specifically focusing on the `message_links` and `time_mentions`.

These enhancements improve the reliability and testing coverage of the
`transform_content` method.

tests/ui_tools/test_messages.py

@@ -1593,6 +1593,96 @@ def test_transform_content(self, mocker, raw_html, expected_content):
         rendered_text = Text(content)
         assert rendered_text.text == expected_content
 
+    @pytest.mark.parametrize(
+        "raw_html, expected_message_links",
+        [
+            (
+                """
+                <p><a href="https://github.com/zulip/zulip-terminal/pull/1">https://github.com/zulip/zulip-terminal/pull/1</a></p>
+                """,
+                {
+                    "https://github.com/zulip/zulip-terminal/pull/1": (
+                        "github.com",
+                        1,
+                        True,
+                    )
+                },
+            ),
+            (
+                """
+                <p><a href="https://foo.com">https://foo.com</a></p>
+                """,
+                {"https://foo.com": ("https://foo.com", 1, False)},
+            ),
+            (
+                """
+                <p><a href="#narrow/stream/206-zulip-terminal/topic/announce">https://chat.zulip.zulip/#narrow/stream/206-zulip-terminal/topic/announce</a></p>
+                """,
+                {
+                    "https://chat.zulip.zulip#narrow/stream/206-zulip-terminal/topic/announce": (  # noqa: E501
+                        "https://chat.zulip.zulip/#narrow/stream/206-zulip-terminal/topic/announce",
+                        1,
+                        True,
+                    )
+                },
+            ),
+        ],
+    )
+    def test_transform_content_message_links(
+        self, mocker, raw_html, expected_message_links
+    ) -> None:
+        _, message_links, *_ = MessageBox.transform_content(raw_html, SERVER_URL)
+
+        assert message_links == expected_message_links
+
+    @pytest.mark.parametrize(
+        "raw_html, expected_time_mentions",
+        [
+            (
+                """
+                <p><time datetime="2024-05-29T11:30:00Z">2024-05-29T17:00:00+05:30</time></p>
+                """,  # noqa: E501
+                [
+                    (
+                        "Wed, May 29 2024, 17:00 (IST)",
+                        "Original text was 2024-05-29T17:00:00+05:30",
+                    )
+                ],
+            ),
+            (
+                """
+                <p><time datetime="3000-06-01T14:00:00Z">3000-06-01T19:30:00+05:30</time></p>
+                """,  # noqa: E501
+                [
+                    (
+                        "Sun, Jun 1 3000, 19:30 (IST)",
+                        "Original text was 3000-06-01T19:30:00+05:30",
+                    )
+                ],
+            ),
+            (
+                """
+                <p><time datetime="1947-08-14T19:47:00Z">1947-08-15T01:17:00+05:30</time></p>
+                """,  # noqa: E501
+                [
+                    (
+                        "Fri, Aug 15 1947, 1:17 (IST)",
+                        "Original text was 1947-08-15T01:17:00+05:30",
+                    )
+                ],
+            ),
+        ],
+    )
+    def test_transform_content_time_mentions(
+        self, mocker, raw_html, expected_time_mentions
+    ) -> None:
+        mocker.patch(
+            MODULE + ".get_localzone", return_value=pytz.timezone("Asia/Kolkata")
+        )
+        _, _, time_mentions, *_ = MessageBox.transform_content(raw_html, SERVER_URL)
+
+        assert time_mentions == expected_time_mentions
+
     # FIXME This is the same parametrize as MsgInfoView:test_height_reactions
     @pytest.mark.parametrize(
         "to_vary_in_each_message, expected_text, expected_attributes",