Test FitsHeader#keyword method

composer.json

@@ -13,7 +13,8 @@
         "phpunit/phpunit": "^11.3"
     },
     "scripts": {
-        "run-pstan": "vendor/bin/phpstan analyze src/ --level 6"
+        "run-pstan": "vendor/bin/phpstan analyze src/ --level 6",
+        "run-tests": "vendor/bin/phpunit tests/ --display-warnings"
     },
     "license": "MIT",
     "autoload": {

tests/FitsHeaderTest.php

@@ -30,5 +30,30 @@ final class FitsHeaderTest extends TestCase
             '86'
         );
     }
+
+    public function testKeyword(): void
+    {
+        $keyword = $this->header->keyword('NAXIS1');
+
+        // Probably useless... (covered by PHPStan)
+        $this->assertInstanceOf(Dumbastro\FitsPhp\Keyword::class, $keyword);
+
+        $this->assertEquals($keyword->value, 2448);
+
+        $keyword = $this->header->keyword('EQUINOX');
+
+        $this->assertEquals(trim($keyword->value), '2000.');
+    }
+
+    /**
+    * @todo This fails for COMMENT keywords
+    public function testToString(): void
+    {
+        $headerBlock = $this->fits->headerBlock;
+        $headerString = $this->header->toString();
+
+        $this->assertEquals($headerBlock, $headerString);
+    }
+    */
 }