Change read() to return null on empty instead of Exception

exercism · Feb 22, 2024 · bc9f553 · bc9f553
1 parent c07b00d
commit bc9f553
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Showing 2 changed files with 5 additions and 29 deletions.
diff --git a/exercises/practice/circular-buffer/.meta/example.php b/exercises/practice/circular-buffer/.meta/example.php
@@ -28,10 +28,6 @@ class BufferFullError extends Exception
 {
 }
 
-class BufferEmptyError extends Exception
-{
-}
-
 class CircularBuffer
 {
     private int $capacity;
@@ -47,13 +43,10 @@ public function __construct($capacity)
         $this->writePosition = 0;
     }
 
-    /**
-     * @throws BufferEmptyError
-     */
     public function read()
     {
         if ($this->isEmpty()) {
-            throw new BufferEmptyError();
+            return null;
         }
         $value = $this->buffer[$this->readPosition];
         $this->buffer[$this->readPosition] = null;
@@ -74,7 +67,6 @@ public function write($item): void
     }
 
     /**
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function forceWrite($item): void

diff --git a/exercises/practice/circular-buffer/CircularBufferTest.php b/exercises/practice/circular-buffer/CircularBufferTest.php
@@ -10,18 +10,15 @@ class CircularBufferTest extends TestCase
 {
     /**
      * uuid: 28268ed4-4ff3-45f3-820e-895b44d53dfa
-     * @throws BufferEmptyError
      */
     public function testReadingEmptyBufferShouldFail(): void
     {
         $buffer = new CircularBuffer(1);
-        $this->expectException(BufferEmptyError::class);
-        $buffer->read();
+        $this->assertNull($buffer->read());
     }
 
     /**
      * uuid: 2e6db04a-58a1-425d-ade8-ac30b5f318f3
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testCanReadAnItemJustWritten(): void
@@ -33,21 +30,18 @@ public function testCanReadAnItemJustWritten(): void
 
     /**
      * uuid: 90741fe8-a448-45ce-be2b-de009a24c144
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testEachItemMayOnlyBeReadOnce(): void
     {
         $buffer = new CircularBuffer(1);
         $buffer->write('1');
         $this->assertSame('1', $buffer->read());
-        $this->expectException(BufferEmptyError::class);
-        $buffer->read();
+        $this->assertNull($buffer->read());
     }
 
     /**
      * uuid: be0e62d5-da9c-47a8-b037-5db21827baa7
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testItemsAreReadInTheOrderTheyAreWritten(): void
@@ -73,7 +67,6 @@ public function testFullBufferCantBeWrittenTo(): void
 
     /**
      * uuid: 547d192c-bbf0-4369-b8fa-fc37e71f2393
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testAReadFreesUpCapacityForAnotherWrite(): void
@@ -87,7 +80,6 @@ public function testAReadFreesUpCapacityForAnotherWrite(): void
 
     /**
      * uuid: 04a56659-3a81-4113-816b-6ecb659b4471
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testReadPositionIsMaintainedEvenAcrossMultipleWrites(): void
@@ -110,13 +102,11 @@ public function testItemsClearedOutOfBufferCantBeRead(): void
         $buffer = new CircularBuffer(1);
         $buffer->write('1');
         $buffer->clear();
-        $this->expectException(BufferEmptyError::class);
-        $buffer->read();
+        $this->assertNull($buffer->read());
     }
 
     /**
      * uuid: 45f3ae89-3470-49f3-b50e-362e4b330a59
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testClearFreesUpCapacityForAnotherWrite(): void
@@ -130,7 +120,6 @@ public function testClearFreesUpCapacityForAnotherWrite(): void
 
     /**
      * uuid: e1ac5170-a026-4725-bfbe-0cf332eddecd
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testClearDoesNothingOnEmptyBuffer(): void
@@ -143,7 +132,6 @@ public function testClearDoesNothingOnEmptyBuffer(): void
 
     /**
      * uuid: 9c2d4f26-3ec7-453f-a895-7e7ff8ae7b5b
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testForceWriteActsLikeWriteOnNonFullBuffer(): void
@@ -157,7 +145,6 @@ public function testForceWriteActsLikeWriteOnNonFullBuffer(): void
 
     /**
      * uuid: 880f916b-5039-475c-bd5c-83463c36a147
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testForceWriteReplacesTheOldestItemOnFullBuffer(): void
@@ -172,7 +159,6 @@ public function testForceWriteReplacesTheOldestItemOnFullBuffer(): void
 
     /**
      * uuid: bfecab5b-aca1-4fab-a2b0-cd4af2b053c3
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testForceWriteReplacesTheOldestItemRemainingInBufferFollowingARead(): void
@@ -191,7 +177,6 @@ public function testForceWriteReplacesTheOldestItemRemainingInBufferFollowingARe
 
     /**
      * uuid: 9cebe63a-c405-437b-8b62-e3fdc1ecec5a
-     * @throws BufferEmptyError
      * @throws BufferFullError
      */
     public function testInitialClearDoesNotAffectWrappingAround(): void
@@ -204,7 +189,6 @@ public function testInitialClearDoesNotAffectWrappingAround(): void
         $buffer->forceWrite('4');
         $this->assertSame('3', $buffer->read());
         $this->assertSame('4', $buffer->read());
-        $this->expectException(BufferEmptyError::class);
-        $buffer->read();
+        $this->assertNull($buffer->read());
     }
 }