diff --git a/tests/ContrastTest.php b/tests/ContrastTest.php
index d8f8453..d361124 100644
--- a/tests/ContrastTest.php
+++ b/tests/ContrastTest.php
@@ -1,5 +1,6 @@
 <?php
 
+use Spatie\Color\Hex;
 use function PHPUnit\Framework\assertSame;
 
 use Spatie\Color\Color;
@@ -12,3 +13,17 @@
 it('can calculate contrast from another format', function (Color $a, Color $b, float $contrast) {
     assertSame($contrast, Contrast::ratio($a->toRgba(), $b->toHsl()));
 })->with('contrast_colors');
+
+it('calculates the luminance correctly for a white color', function () {
+    $white = Hex::fromString('#FFFFFF');
+    $luminance = Contrast::calculateLuminance($white);
+
+    expect($luminance)->toBe(1.0);
+});
+
+it('calculates the luminance correctly for a black color', function () {
+    $black = Hex::fromString('#000000');
+    $luminance = Contrast::calculateLuminance($black);
+
+    expect($luminance)->toBe(0.0);
+});
diff --git a/tests/Datasets/Colors.php b/tests/Datasets/Colors.php
index b1dd759..ae2d1c0 100644
--- a/tests/Datasets/Colors.php
+++ b/tests/Datasets/Colors.php
@@ -69,9 +69,9 @@
     [Hex::fromString('#ffffff'), Hex::fromString('#ffffff'), 1.0],
     [Hex::fromString('#ffffff'), Hex::fromString('#000000'), 21.0],
     [Hex::fromString('#000000'), Hex::fromString('#000000'), 1.0],
-    [Hex::fromString('#faebd7'), Hex::fromString('#8a2be2'), 5.0],
-    [Hex::fromString('#ff1493'), Hex::fromString('#cd5c5c'), 1.0],
-    [Hex::fromString('#f0fff0'), Hex::fromString('#191970'), 15.0],
+    [Hex::fromString('#faebd7'), Hex::fromString('#8a2be2'), 5.16],
+    [Hex::fromString('#ff1493'), Hex::fromString('#cd5c5c'), 1.08],
+    [Hex::fromString('#f0fff0'), Hex::fromString('#191970'), 15.05],
 ]);
 
 dataset('hsla_string_and_rgb_values', function () {