circular-buffer: Update the tests following the canonical data (exercism#1047)

* circular-buffer: Update the tests following the canonical data

Author: elyssonmr

exercises/circular-buffer/circular_buffer_test.py

@@ -7,43 +7,41 @@
 )
 
 
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.0.1
+
 class CircularBufferTest(unittest.TestCase):
     def test_read_empty_buffer(self):
         buf = CircularBuffer(1)
         with self.assertRaises(BufferEmptyException):
             buf.read()
 
+    def test_read_just_written_item(self):
+        buf = CircularBuffer(1)
+        buf.write('1')
+        self.assertEqual(buf.read(), '1')
+
     def test_write_and_read_back_one_item(self):
         buf = CircularBuffer(1)
         buf.write('1')
-        self.assertEqual('1', buf.read())
+        self.assertEqual(buf.read(), '1')
         with self.assertRaises(BufferEmptyException):
             buf.read()
 
-    def test_write_and_read_back_multiple_items(self):
+    def test_write_and_read_back_multiple_items_ordered(self):
         buf = CircularBuffer(2)
         buf.write('1')
         buf.write('2')
         self.assertEqual(buf.read(), '1')
         self.assertEqual(buf.read(), '2')
-        with self.assertRaises(BufferEmptyException):
-            buf.read()
 
-    def test_clearing_buffer(self):
-        buf = CircularBuffer(3)
-        for c in '123':
-            buf.write(c)
-        buf.clear()
-        with self.assertRaises(BufferEmptyException):
-            buf.read()
+    def test_full_buffer_cant_written(self):
+        buf = CircularBuffer(1)
         buf.write('1')
-        buf.write('2')
-        self.assertEqual(buf.read(), '1')
-        buf.write('3')
-        self.assertEqual(buf.read(), '2')
+        with self.assertRaises(BufferFullException):
+            buf.write('2')
 
     def test_alternate_write_and_read(self):
-        buf = CircularBuffer(2)
+        buf = CircularBuffer(1)
         buf.write('1')
         self.assertEqual(buf.read(), '1')
         buf.write('2')
@@ -53,56 +51,64 @@ def test_read_back_oldest_item(self):
         buf = CircularBuffer(3)
         buf.write('1')
         buf.write('2')
-        buf.read()
+        self.assertEqual(buf.read(), '1')
         buf.write('3')
-        buf.read()
+        self.assertEqual(buf.read(), '2')
         self.assertEqual(buf.read(), '3')
 
-    def test_write_full_buffer(self):
-        buf = CircularBuffer(2)
+    def test_clearing_buffer(self):
+        buf = CircularBuffer(1)
         buf.write('1')
-        buf.write('2')
-        with self.assertRaises(BufferFullException):
-            buf.write('A')
+        buf.clear()
+        with self.assertRaises(BufferEmptyException):
+            buf.read()
 
-    def test_overwrite_full_buffer(self):
-        buf = CircularBuffer(2)
+    def test_clear_free_buffer_for_write(self):
+        buf = CircularBuffer(1)
         buf.write('1')
+        buf.clear()
         buf.write('2')
-        buf.overwrite('A')
         self.assertEqual(buf.read(), '2')
-        self.assertEqual(buf.read(), 'A')
-        with self.assertRaises(BufferEmptyException):
-            buf.read()
+
+    def test_clear_does_nothin_empty_buffer(self):
+        buf = CircularBuffer(1)
+        buf.clear()
+        buf.write('1')
+        self.assertEqual(buf.read(), '1')
 
     def test_overwrite_non_full_buffer(self):
         buf = CircularBuffer(2)
-        buf.overwrite('1')
+        buf.write('1')
         buf.overwrite('2')
         self.assertEqual(buf.read(), '1')
         self.assertEqual(buf.read(), '2')
-        with self.assertRaises(BufferEmptyException):
-            buf.read()
 
-    def test_alternate_read_and_overwrite(self):
-        buf = CircularBuffer(5)
-        for c in '123':
-            buf.write(c)
-        buf.read()
-        buf.read()
+    def test_overwrite_replaces_oldest_item(self):
+        buf = CircularBuffer(2)
+        buf.write('1')
+        buf.write('2')
+        buf.overwrite('3')
+        self.assertEqual(buf.read(), '2')
+        self.assertEqual(buf.read(), '3')
+
+    def test_write_full_buffer(self):
+        buf = CircularBuffer(2)
+        buf.write('1')
+        buf.write('2')
+        with self.assertRaises(BufferFullException):
+            buf.write('A')
+
+    def test_over_write_replaces_oldest_remaning_item(self):
+        buf = CircularBuffer(3)
+        buf.write('1')
+        buf.write('2')
+        buf.write('3')
+        self.assertEqual(buf.read(), '1')
         buf.write('4')
-        buf.read()
-        for c in '5678':
-            buf.write(c)
-        buf.overwrite('A')
-        buf.overwrite('B')
-        self.assertEqual(buf.read(), '6')
-        self.assertEqual(buf.read(), '7')
-        self.assertEqual(buf.read(), '8')
-        self.assertEqual(buf.read(), 'A')
-        self.assertEqual(buf.read(), 'B')
-        with self.assertRaises(BufferEmptyException):
-            buf.read()
+        buf.overwrite('5')
+        self.assertEqual(buf.read(), '3')
+        self.assertEqual(buf.read(), '4')
+        self.assertEqual(buf.read(), '5')
 
 
 if __name__ == '__main__':