Add isEmpty method to string and integer types with tests for consistent behavior

Author: georgedeploy

src/Abstract/Primitive/PrimitiveTypeInterface.php

@@ -5,6 +5,7 @@
 namespace PhpTypedValues\Abstract\Primitive;
 
 use JsonSerializable;
+use PhpTypedValues\Abstract\Shared\IsEmptyInterface;
 use PhpTypedValues\Abstract\TypeInterface;
 use PhpTypedValues\Exception\TypeException;
 use PhpTypedValues\Undefined\Alias\Undefined;
@@ -23,7 +24,7 @@
  *
  * @psalm-immutable
  */
-interface PrimitiveTypeInterface extends TypeInterface, JsonSerializable
+interface PrimitiveTypeInterface extends TypeInterface, JsonSerializable, IsEmptyInterface
 {
     /**
      * Create an instance from a validated string representation.

src/Abstract/Shared/IsEmptyInterface.php

@@ -12,7 +12,7 @@
 interface IsEmptyInterface
 {
     /**
-     * Returns if the Object value is empty.
+     * Returns true if the Object value is empty.
      */
     public function isEmpty(): bool;
 }

src/Integer/IntegerStandard.php

@@ -92,4 +92,9 @@ public function jsonSerialize(): int
     {
         return $this->value();
     }
+
+    public function isEmpty(): bool
+    {
+        return false;
+    }
 }

src/Integer/IntegerWeekDay.php

@@ -116,4 +116,9 @@ public function __toString(): string
     {
         return $this->toString();
     }
+
+    public function isEmpty(): bool
+    {
+        return false;
+    }
 }

src/Integer/MariaDb/IntegerTiny.php

@@ -112,4 +112,9 @@ public function __toString(): string
     {
         return $this->toString();
     }
+
+    public function isEmpty(): bool
+    {
+        return false;
+    }
 }

src/String/MariaDb/StringDecimal.php

@@ -119,4 +119,10 @@ public function __toString(): string
     {
         return $this->toString();
     }
+
+    public function isEmpty(): bool
+    {
+        // Decimal values are never empty by construction; constructor rejects empty strings
+        return false;
+    }
 }

src/String/StringCountryCode.php

@@ -97,6 +97,11 @@ public function __toString(): string
         return $this->toString();
     }
 
+    public function isEmpty(): bool
+    {
+        return false;
+    }
+
     /**
      * ISO 3166-1 alpha-2 codes used for validation.
      *

src/String/StringEmail.php

@@ -93,4 +93,9 @@ public function __toString(): string
     {
         return $this->toString();
     }
+
+    public function isEmpty(): bool
+    {
+        return false;
+    }
 }

src/String/StringJson.php

@@ -123,4 +123,10 @@ public function __toString(): string
     {
         return $this->toString();
     }
+
+    public function isEmpty(): bool
+    {
+        // JSON values are never empty by construction; constructor rejects empty strings
+        return false;
+    }
 }

src/String/StringNonBlank.php

@@ -91,4 +91,9 @@ public function __toString(): string
     {
         return $this->toString();
     }
+
+    public function isEmpty(): bool
+    {
+        return false;
+    }
 }