diff --git a/CMYK.zig b/CMYK.zig
index 738c5dcc631d1c2c6abd6adf4382b4821838c67f..1bcf2914fb6ee01858b407fd3668fb7cb22b89b3 100644
--- a/CMYK.zig
+++ b/CMYK.zig
@@ -27,3 +27,13 @@ pub fn initCMYKA(c: f32, m: f32, y: f32, k: f32, a: f32) Self {
 pub fn eql(x: Self, y: Self) bool {
     return x.c == y.c and x.m == y.m and x.y == y.y and x.k == y.k and x.a == y.a;
 }
+
+pub fn to_array(x: Self) [5]f32 {
+    return .{
+        x.c,
+        x.m,
+        x.y,
+        x.k,
+        x.a,
+    };
+}
diff --git a/HSL.zig b/HSL.zig
index e88ad72d5c87b33b6db69088fbda5da5512545de..014d251ac50795416aae9790e839cbfce4967377 100644
--- a/HSL.zig
+++ b/HSL.zig
@@ -2,6 +2,7 @@
 
 const std = @import("std");
 const Self = @This();
+const _x = @import("./_x.zig");
 
 h: f32, // hue
 s: f32, // saturation
@@ -24,3 +25,5 @@ pub fn initHSLA(h: f32, s: f32, l: f32, a: f32) Self {
 pub fn eql(x: Self, y: Self) bool {
     return x.h == y.h and x.s == y.s and x.l == y.l and x.a == y.a;
 }
+
+pub usingnamespace _x.mixin(@This(), f32, .h, .s, .l);
diff --git a/HSV.zig b/HSV.zig
index 7db51d0da3c2cf12a5f161c6b1f087071598508c..a6effd09afebde58e337a141eff10bd734846422 100644
--- a/HSV.zig
+++ b/HSV.zig
@@ -2,6 +2,7 @@
 
 const std = @import("std");
 const Self = @This();
+const _x = @import("./_x.zig");
 
 h: f32, // hue
 s: f32, // saturation
@@ -24,3 +25,5 @@ pub fn initHSVA(h: f32, s: f32, v: f32, a: f32) Self {
 pub fn eql(x: Self, y: Self) bool {
     return x.h == y.h and x.s == y.s and x.v == y.v and x.a == y.a;
 }
+
+pub usingnamespace _x.mixin(@This(), f32, .h, .s, .v);
diff --git a/LinearRgb.zig b/LinearRgb.zig
index 4cf3c4cad6045990f94c0f7a60f9ed2a46685023..2e143cc37e0b864af697ffe6f11ca034ba5c5e98 100644
--- a/LinearRgb.zig
+++ b/LinearRgb.zig
@@ -2,6 +2,7 @@
 
 const std = @import("std");
 const Self = @This();
+const _x = @import("./_x.zig");
 
 r: f32, // red
 g: f32, // green
@@ -28,3 +29,5 @@ pub fn eql(x: Self, y: Self) bool {
 pub fn relative_luminance(x: Self) f32 {
     return (0.2126 * x.r) + (0.7152 * x.g) + (0.0722 * x.b);
 }
+
+pub usingnamespace _x.mixin(@This(), f32, .r, .g, .b);
diff --git a/_x.zig b/_x.zig
index 2bb5c9ba0c5bd95667a181bafae2be9e731ca4c0..5a0bd07ff9b35c860a9a2b4167c482c3cf676eb6 100644
--- a/_x.zig
+++ b/_x.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 
 pub fn mixin(
     comptime T: type,
+    comptime I: type,
     comptime f1: std.meta.FieldEnum(T),
     comptime f2: std.meta.FieldEnum(T),
     comptime f3: std.meta.FieldEnum(T),
@@ -25,7 +26,7 @@ pub fn mixin(
             return x;
         }
 
-        pub fn to_array(x: T, comptime I: type) [4]I {
+        pub fn to_array(x: T) [4]I {
             return .{
                 @field(x, @tagName(f1)),
                 @field(x, @tagName(f2)),
diff --git a/build.zig b/build.zig
index 3ca210217535d10e2f201a8b24a219328fd2fd0b..14bc91256a79ccb7fc1ca4159f415626ae409fd9 100644
--- a/build.zig
+++ b/build.zig
@@ -25,6 +25,15 @@ pub fn build(b: *std.Build) void {
     const run_step = b.step("run", "Run the app");
     run_step.dependOn(&run_cmd.step);
 
-    const test_step = b.step("test", "dummy test step to pass CI checks");
-    _ = test_step;
+    const tests = b.addTest(.{
+        .root_source_file = b.path("test.zig"),
+        .target = target,
+        .optimize = mode,
+    });
+    deps.addAllTo(tests);
+
+    const test_step = b.step("test", "Run all library tests");
+    const tests_run = b.addRunArtifact(tests);
+    tests_run.has_side_effects = true;
+    test_step.dependOn(&tests_run.step);
 }
diff --git a/sRGB.zig b/sRGB.zig
index 68bc85a8f815155ce078e19d48b29ae96c906745..8114e489097f202c7244b2660cdac7182a4ab6c8 100644
--- a/sRGB.zig
+++ b/sRGB.zig
@@ -73,7 +73,7 @@ pub fn format(x: Self, comptime fmt: []const u8, options: std.fmt.FormatOptions,
     });
 }
 
-pub usingnamespace _x.mixin(@This(), .r, .g, .b);
+pub usingnamespace _x.mixin(@This(), u8, .r, .g, .b);
 
 pub fn to_linear_rgb(x: Self) color.LinearRgb {
     const lut = comptime blk: {
@@ -94,7 +94,7 @@ pub fn to_linear_rgb(x: Self) color.LinearRgb {
 }
 
 pub fn to_float(x: Self) Float {
-    return Self{
+    return .{
         .r = @as(f32, @floatFromInt(x.r)) / 255.0,
         .g = @as(f32, @floatFromInt(x.g)) / 255.0,
         .b = @as(f32, @floatFromInt(x.b)) / 255.0,
@@ -119,9 +119,9 @@ pub fn to_hsl(x: Self) color.HSL {
     const delta = cmax - cmin;
     const h = blk: {
         if (delta == 0) break :blk 0;
-        if (cmax == f.r) break :blk ((((f.g - f.b) / delta) % 6) * 60) % 360;
-        if (cmax == f.g) break :blk ((((f.b - f.r) / delta) + 2) * 60) % 360;
-        if (cmax == f.b) break :blk ((((f.r - f.g) / delta) + 4) * 60) % 360;
+        if (cmax == f.r) break :blk @rem(((f.g - f.b) / delta), 6.0) / 6.0;
+        if (cmax == f.g) break :blk (((f.b - f.r) / delta) + 2) / 6.0;
+        if (cmax == f.b) break :blk (((f.r - f.g) / delta) + 4) / 6.0;
         unreachable;
     };
     const l = (cmax + cmin) / 2;
@@ -137,9 +137,9 @@ pub fn to_hsv(x: Self) color.HSV {
     const delta = cmax - cmin;
     const h = blk: {
         if (delta == 0) break :blk 0;
-        if (cmax == f.r) break :blk ((((f.g - f.b) / delta) % 6) * 60) % 360;
-        if (cmax == f.g) break :blk ((((f.b - f.r) / delta) + 2) * 60) % 360;
-        if (cmax == f.b) break :blk ((((f.r - f.g) / delta) + 4) * 60) % 360;
+        if (cmax == f.r) break :blk (@rem(((f.g - f.b) / delta), 6.0) / 6.0);
+        if (cmax == f.g) break :blk ((((f.b - f.r) / delta) + 2) / 6.0);
+        if (cmax == f.b) break :blk ((((f.r - f.g) / delta) + 4) / 6.0);
         unreachable;
     };
     const s = if (cmax == 0) 0 else delta / cmax;
diff --git a/test.zig b/test.zig
new file mode 100644
index 0000000000000000000000000000000000000000..6a976c9fe59c29eedba6b8920fd684f31e70052d
--- /dev/null
+++ b/test.zig
@@ -0,0 +1,47 @@
+const std = @import("std");
+const color = @import("color");
+
+test {
+    // https://www.colorhexa.com/4fc3f7
+    const o = color.sRGB.parseHexConst("#4FC3F7");
+    {
+        const r, const g, const b, const a = o.to_array();
+        try std.testing.expect(r == 79);
+        try std.testing.expect(g == 195);
+        try std.testing.expect(b == 247);
+        try std.testing.expect(a == 255);
+    }
+    {
+        // 68% cyan, 21.1% magenta, 0% yellow and 3.1% black
+        const c, const m, const y, const k, const a = o.to_cmyk().to_array();
+        try std.testing.expectApproxEqAbs(0.68, c, 0.01);
+        try std.testing.expectApproxEqAbs(0.21, m, 0.01);
+        try std.testing.expectApproxEqAbs(0.00, y, 0.01);
+        try std.testing.expectApproxEqAbs(0.03, k, 0.01);
+        try std.testing.expect(a == 1.0);
+    }
+    {
+        // 198.6°, 91.3, 63.9
+        const h, const s, const l, const a = o.to_hsl().to_array();
+        try std.testing.expectApproxEqAbs(0.552, h, 0.001);
+        try std.testing.expectApproxEqAbs(0.913, s, 0.001);
+        try std.testing.expectApproxEqAbs(0.639, l, 0.001);
+        try std.testing.expect(a == 1.0);
+    }
+    {
+        // 198.6°, 68, 96.9
+        const h, const s, const v, const a = o.to_hsv().to_array();
+        try std.testing.expectApproxEqAbs(0.552, h, 0.001);
+        try std.testing.expectApproxEqAbs(0.680, s, 0.001);
+        try std.testing.expectApproxEqAbs(0.969, v, 0.001);
+        try std.testing.expect(a == 1.0);
+    }
+    {
+        // 0.0781874218051863, 0.545724461370187, 0.930110858375424
+        const r, const g, const b, const a = o.to_linear_rgb().to_array();
+        try std.testing.expectApproxEqAbs(0.078, r, 0.001);
+        try std.testing.expectApproxEqAbs(0.545, g, 0.001);
+        try std.testing.expectApproxEqAbs(0.930, b, 0.001);
+        try std.testing.expect(a == 1.0);
+    }
+}