Skip warnings in test contexts.

src/defaults.js

@@ -3,4 +3,10 @@ export default {
 	gamut_mapping: "css",
 	precision: 5,
 	deltaE: "76", // Default deltaE method
+	verbose: globalThis?.process?.env?.NODE_ENV?.toLowerCase() !== "test",
+	warn: function warn (msg) {
+		if (this.verbose) {
+			globalThis?.console?.warn?.(msg);
+		}
+	},
 };

src/deltaE/deltaE2000.js

@@ -1,3 +1,4 @@
+import defaults from "../defaults.js";
 import lab from "../spaces/lab.js";
 import lch from "../spaces/lch.js";
 
@@ -107,7 +108,7 @@ export default function (color, sample, {kL = 1, kC = 1, kH = 1} = {}) {
 		Δh = hdiff + 360;
 	}
 	else {
-		console.log("the unthinkable has happened");
+		defaults.warn("the unthinkable has happened");
 	}
 
 	// weighted Hue difference, more for larger Chroma

src/parse.js

@@ -1,6 +1,7 @@
 import * as util from "./util.js";
 import hooks from "./hooks.js";
 import ColorSpace from "./space.js";
+import defaults from "./defaults.js";
 
 const noneTypes = new Set(["<number>", "<percentage>", "<angle>"]);
 
@@ -104,12 +105,12 @@ export default function parse (str, {meta} = {}) {
 						}
 
 						if (colorSpec.id.startsWith("--") && !id.startsWith("--")) {
-							console.warn(`${space.name} is a non-standard space and not currently supported in the CSS spec. ` +
-							             `Use prefixed color(${colorSpec.id}) instead of color(${id}).`);
+							defaults.warn(`${space.name} is a non-standard space and not currently supported in the CSS spec. ` +
+							              `Use prefixed color(${colorSpec.id}) instead of color(${id}).`);
 						}
 						if (id.startsWith("--") && !colorSpec.id.startsWith("--")) {
-							console.warn(`${space.name} is a standard space and supported in the CSS spec. ` +
-							             `Use color(${colorSpec.id}) instead of prefixed color(${id}).`);
+							defaults.warn(`${space.name} is a standard space and supported in the CSS spec. ` +
+							              `Use color(${colorSpec.id}) instead of prefixed color(${id}).`);
 						}
 
 						return {spaceId: space.id, coords, alpha};