Change format_datetime implementation according to feature

plume-models/src/posts.rs

@@ -950,6 +950,7 @@ mod tests {
     use diesel::Connection;
     use serde_json::{json, to_value};
 
+    #[cfg(feature = "postgres")]
     fn format_datetime(dt: &NaiveDateTime) -> String {
         format!(
             "{:04}-{:02}-{:02}T{:02}:{:02}:{:02}.{:06}Z",
@@ -963,6 +964,19 @@ mod tests {
         )
     }
 
+    #[cfg(feature = "sqlite")]
+    fn format_datetime(dt: &NaiveDateTime) -> String {
+        format!(
+            "{:04}-{:02}-{:02}T{:02}:{:02}:{:02}Z",
+            dt.year(),
+            dt.month(),
+            dt.day(),
+            dt.hour(),
+            dt.minute(),
+            dt.second()
+        )
+    }
+
     fn prepare_activity(conn: &DbConn) -> (Post, Mention, Vec<Post>, Vec<User>, Vec<Blog>) {
         let (posts, users, blogs) = fill_database(conn);
         let post = &posts[0];