[ty] Speedup the known_class_doesnt_fallback_to_unknown_unexpectedly_on_low_python_version test (#19760)

crates/ty_python_semantic/src/types/class.rs

@@ -4676,22 +4676,41 @@ mod tests {
     fn known_class_doesnt_fallback_to_unknown_unexpectedly_on_low_python_version() {
         let mut db = setup_db();
 
-        for class in KnownClass::iter() {
+        // First, collect the `KnownClass` variants
+        // and sort them according to the version they were added in.
+        // This makes the test far faster as it minimizes the number of times
+        // we need to change the Python version in the loop.
+        let mut classes: Vec<(KnownClass, PythonVersion)> = KnownClass::iter()
+            .map(|class| {
                 let version_added = match class {
                     KnownClass::UnionType => PythonVersion::PY310,
-                KnownClass::BaseExceptionGroup | KnownClass::ExceptionGroup => PythonVersion::PY311,
+                    KnownClass::BaseExceptionGroup | KnownClass::ExceptionGroup => {
+                        PythonVersion::PY311
+                    }
                     KnownClass::GenericAlias => PythonVersion::PY39,
                     KnownClass::KwOnly => PythonVersion::PY310,
                     KnownClass::Member | KnownClass::Nonmember => PythonVersion::PY311,
                     _ => PythonVersion::PY37,
                 };
+                (class, version_added)
+            })
+            .collect();
 
-            Program::get(&db)
+        classes.sort_unstable_by_key(|(_, version)| *version);
+
+        let program = Program::get(&db);
+        let mut current_version = program.python_version(&db);
+
+        for (class, version_added) in classes {
+            if version_added != current_version {
+                program
                     .set_python_version_with_source(&mut db)
                     .to(PythonVersionWithSource {
                         version: version_added,
                         source: PythonVersionSource::default(),
                     });
+                current_version = version_added;
+            }
 
             assert_ne!(
                 class.to_instance(&db),