Fix config loading, speed thresholds and block selection; add tests, README, CLAUDE.md

das_tetris_gui.py

@@ -85,8 +85,7 @@ class TetrisGame:
         else:
             self.current_block = self.next_block
             self.current_block_rotation = self.next_block_rotation
-            while self.current_block == self.next_block:
-                self.next_block = self.choice_random_block()
+            self.next_block = self.choice_random_block(exclude=self.current_block)
             self.next_block_rotation = 0
 
         self.current_block_x = self.width // 2 - 2
@@ -97,11 +96,11 @@ class TetrisGame:
                                     self.current_block_rotation, self.current_block):
             self.game_over = True
 
-    def choice_random_block(self) -> BLOCK_TYPE:
-        block: BLOCK_TYPE = random.choice(list(BLOCK_TYPE))
-        while self.get_block_min_score(block) > self.score:
-            block = random.choice(list(BLOCK_TYPE))
-        return block
+    def choice_random_block(self, exclude: BLOCK_TYPE = None) -> BLOCK_TYPE:
+        """Choose a random block allowed at the current score, avoiding `exclude` when possible"""
+        allowed = [block for block in BLOCK_TYPE if self.get_block_min_score(block) <= self.score]
+        candidates = [block for block in allowed if block != exclude] or allowed
+        return random.choice(candidates)
 
     def get_block_shape(self, block_type: BLOCK_TYPE, rotation: int) -> List[List[int]]:
         """Get the shape matrix for a block at specific rotation"""
@@ -220,20 +219,21 @@ class TetrisGame:
         elapsed = (current_ticks - self.last_time) / 1000.0  # Convert to seconds
         self.last_time = current_ticks
 
+        # Highest threshold first, otherwise only the first branch is ever reached
         if cfg.HIGH_SCORE_INC_SPEED:
-            if self.score > 5000:
-                self.fall_speed = 0.55
+            if self.score > 15000:
+                self.fall_speed = 0.65
             elif self.score > 10000:
                 self.fall_speed = 0.6
-            elif self.score > 15000:
-                self.fall_speed = 0.65
+            elif self.score > 5000:
+                self.fall_speed = 0.55
         else:
-            if self.score > 5000:
-                self.fall_speed = 0.45
+            if self.score > 15000:
+                self.fall_speed = 0.35
             elif self.score > 10000:
                 self.fall_speed = 0.4
-            elif self.score > 15000:
-                self.fall_speed = 0.35
+            elif self.score > 5000:
+                self.fall_speed = 0.45
 
         if not self.game_over and not self.paused:
             self.fall_time += elapsed