fixed unrunnable suite without scaler

src/suite.py

@@ -36,7 +36,7 @@ from helpers.tags import Tree
 # Tests
 from helpers.test.knn import CVSuiteTestKNN
 
-# from helpers.test.decision_tree import CVSuiteTestDecisionTree
+from helpers.test.decision_tree import CVSuiteTestDecisionTree
 
 ## UI config load
 PROJECT_PATH = pathlib.Path(__file__).parent
@@ -308,6 +308,10 @@ class CVSuite:
             self.log.add(f"Std {label}", std[idx])
 
     def runTest(self, data, event=None):
+        # Don't run the test if there's no scaler
+        if self.scaler is None:
+            return
+        
         output = self.builder.get_object("testdata")
         output.configure(state="normal")
         output.delete(1.0, "end")