Implement Command::asString() method

Author: sebastianbergmann

src/domain/command/Command.php

@@ -0,0 +1,13 @@
+<?php declare(strict_types=1);
+namespace example\caledonia\domain;
+
+/**
+ * @no-named-arguments
+ */
+abstract readonly class Command
+{
+    /**
+     * @return non-empty-string
+     */
+    abstract public function asString(): string;
+}

src/domain/command/PurchaseGoodCommand.php

@@ -1,10 +1,12 @@
 <?php declare(strict_types=1);
 namespace example\caledonia\domain;
 
+use function sprintf;
+
 /**
  * @no-named-arguments
  */
-final readonly class PurchaseGoodCommand
+final readonly class PurchaseGoodCommand extends Command
 {
     private Good $good;
 
@@ -34,4 +36,16 @@ public function amount(): int
     {
         return $this->amount;
     }
+
+    /**
+     * @return non-empty-string
+     */
+    public function asString(): string
+    {
+        return sprintf(
+            'Purchase %d %s',
+            $this->amount,
+            $this->good->value,
+        );
+    }
 }

src/domain/command/SellGoodCommand.php

@@ -1,10 +1,12 @@
 <?php declare(strict_types=1);
 namespace example\caledonia\domain;
 
+use function sprintf;
+
 /**
  * @no-named-arguments
  */
-final readonly class SellGoodCommand
+final readonly class SellGoodCommand extends Command
 {
     private Good $good;
 
@@ -34,4 +36,16 @@ public function amount(): int
     {
         return $this->amount;
     }
+
+    /**
+     * @return non-empty-string
+     */
+    public function asString(): string
+    {
+        return sprintf(
+            'Sell %d %s',
+            $this->amount,
+            $this->good->value,
+        );
+    }
 }

tests/unit/domain/command/PurchaseGoodCommandTest.php

@@ -27,4 +27,11 @@ public function testHasAmount(): void
 
         $this->assertSame(1, $command->amount());
     }
+
+    public function testCanBeRepresentedAsString(): void
+    {
+        $command = new PurchaseGoodCommand(Good::Bread, 1);
+
+        $this->assertSame('Purchase 1 bread', $command->asString());
+    }
 }

tests/unit/domain/command/SellGoodCommandTest.php

@@ -27,4 +27,11 @@ public function testHasAmount(): void
 
         $this->assertSame(1, $command->amount());
     }
+
+    public function testCanBeRepresentedAsString(): void
+    {
+        $command = new SellGoodCommand(Good::Bread, 1);
+
+        $this->assertSame('Sell 1 bread', $command->asString());
+    }
 }