feat: solve day 1 part 1

internal/file/file_test.go

@@ -0,0 +1,21 @@
+package file_test
+
+import (
+	"slices"
+	"testing"
+
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/file"
+)
+
+func TestReadLines(t *testing.T) {
+	expectedLines := []string{
+		"hello",
+		"world",
+	}
+
+	result := file.ReadLines("test.txt")
+
+	if slices.Equal(result, expectedLines) == false {
+		t.Errorf("got %s but expected %s", result, expectedLines)
+	}
+}