diff --git a/.eslintrc.json b/.eslintrc.json
index 5606883..6d48e6b 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -32,7 +32,7 @@
 		"consistent-return": "error",
 		"constructor-super": "warn",
 		"eqeqeq": "error",
-		"eslint-comments/no-use": ["error", {"allow": ["eslint-disable-next-line"]}],
+		"eslint-comments/no-use": ["error", {"allow": ["eslint-disable-next-line", "globals"]}],
 		"indent": ["error", "tab", {"SwitchCase": 1}],
 		"max-depth": ["warn", 4],
 		"max-len": ["warn", {"code": 120, "tabWidth": 4}],
diff --git a/test/canvasAPI.js b/test/canvasAPI.js
new file mode 100644
index 0000000..0979518
--- /dev/null
+++ b/test/canvasAPI.js
@@ -0,0 +1,79 @@
+const canvasAPI = {
+	draw: function draw(canvas){
+		"use strict";
+		
+		canvas.setAttribute("width", 220);
+		canvas.setAttribute("height", 30);
+		
+		const fingerprintText = "BrowserLeaks,com <canvas> 10";
+		
+		const context = canvas.getContext("2d");
+		context.textBaseline = "top";
+		context.font = "14px 'Arial'";
+		context.textBaseline = "alphabetic";
+		context.fillStyle = "#f60";
+		context.fillRect(125, 1, 62, 20);
+		context.fillStyle = "#069";
+		context.fillText(fingerprintText, 2, 15);
+		context.fillStyle = "rgba(102, 204, 0, 07)";
+		context.fillText(fingerprintText, 4, 17);
+		
+		return context;
+	},
+	getIsPointInPath: function getIsPointInPath(context){
+		"use strict";
+		
+		context.beginPath();
+		context.moveTo(20, 19);
+		context.lineTo(40, 19);
+		context.lineTo(30, 30);
+		context.closePath();
+		context.stroke();
+		
+		return context.isPointInPath(30, 19);
+	},
+	getFingerprintData: function getFingerprintData(canvas, context){
+		"use strict";
+		
+		return {
+			imageData: context.getImageData(0, 0, canvas.width, canvas.height),
+			url: canvas.toDataURL(),
+			isPointInPath: canvasAPI.getIsPointInPath(context)
+		};
+	},
+	getFingerprintFromDifferentDocument: function getFingerprintFromDifferentDocument(otherDocument){
+		"use strict";
+	
+		// create window canvas
+		const canvas = document.createElement("canvas");
+	
+		// draw image in window canvas
+		canvasAPI.draw(canvas);
+	
+		// create other canvas and context
+		const otherCanvas = otherDocument.createElement("canvas");
+		otherCanvas.setAttribute("width", 220);
+		otherCanvas.setAttribute("height", 30);
+		const otherContext = otherCanvas.getContext("2d");
+	
+		// copy image from window canvas to iframe context
+		otherContext.drawImage(canvas, 0, 0);
+	
+		return canvasAPI.getFingerprintData(otherCanvas, otherContext);
+	},
+	fingerprint: function fingerprint(windowToUse){
+		"use strict";
+		if (!windowToUse){
+			windowToUse = window;
+		}
+		
+		const canvas = document.createElement("canvas");
+		const context = canvasAPI.draw(canvas);
+		if (windowToUse !== window){
+			return canvasAPI.getFingerprintFromDifferentDocument(windowToUse.document);
+		}
+		else {
+			return this.getFingerprintData(canvas, context);
+		}
+	}
+};
\ No newline at end of file
diff --git a/test/cspTest.js b/test/cspTest.js
index b4b3983..a12ef65 100644
--- a/test/cspTest.js
+++ b/test/cspTest.js
@@ -1,48 +1,4 @@
-
-function draw(canvas){
-	"use strict";
-	
-	canvas.setAttribute("width", 220);
-	canvas.setAttribute("height", 30);
-	
-	const fp_text = "BrowserLeaks,com <canvas> 10";
-	
-	const ctx = canvas.getContext("2d");
-	ctx.textBaseline = "top";
-	ctx.font = "14px 'Arial'";
-	ctx.textBaseline = "alphabetic";
-	ctx.fillStyle = "#f60";
-	ctx.fillRect(125, 1, 62, 20);
-	ctx.fillStyle = "#069";
-	ctx.fillText(fp_text, 2, 15);
-	ctx.fillStyle = "rgba(102, 204, 0, 07)";
-	ctx.fillText(fp_text, 4, 17);
-	
-	return ctx;
-}
-function test(window){
-	"use strict";
-	
-	// create window canvas
-	const canvas = document.createElement("canvas");
-	// draw image in window canvas
-	draw(canvas);
-	return window.HTMLCanvasElement.prototype.toDataURL.call(canvas);
-}
-async function hash(string){
-	"use strict";
-	
-	const buffer = new TextEncoder("utf-8").encode(string);
-	const hash = await crypto.subtle.digest("SHA-256", buffer);
-	const chunks = [];
-	(new Uint32Array(hash)).forEach(function(num){
-		chunks.push(num.toString(16));
-	});
-	return chunks.map(function(chunk){
-		return "0".repeat(8 - chunk.length) + chunk;
-	}).join("");
-}
-
+/* globals testAPI, canvasAPI*/
 const addLine = function(){
 	"use strict";
 	
@@ -60,6 +16,6 @@ addLine("window name after set: " + window.name);
 (async function(){
 	"use strict";
 	
-	const hashValue = await hash(test(window));
+	const hashValue = await testAPI.hash(canvasAPI.fingerprint(window).url);
 	addLine("canvas hash: " + hashValue);
 }());
\ No newline at end of file
diff --git a/test/cspTest.php b/test/cspTest.php
index f4244e4..f7f84f6 100644
--- a/test/cspTest.php
+++ b/test/cspTest.php
@@ -20,6 +20,8 @@ header("Content-Security-Policy: default-src 'none'; img-src 'self'; script-src
 </ul>
 <h2>Tests</h2>
 <div id="results"></div>
+<script src="testAPI.js"></script>
+<script src="canvasAPI.js"></script>
 <script src="cspTest.js"></script>
 </body>
 </html>
\ No newline at end of file
diff --git a/test/performanceTest.html b/test/performanceTest.html
index cbb4a26..10e864a 100644
--- a/test/performanceTest.html
+++ b/test/performanceTest.html
@@ -11,5 +11,6 @@
 Tests the performance of some operations that are affected by CanvasBlocker.
 <div id="log">
 </div>
+<script src="canvasAPI.js"></script>
 <script src="performanceTest.js"></script>
 </body></html>
\ No newline at end of file
diff --git a/test/performanceTest.js b/test/performanceTest.js
index a23a452..6e12781 100644
--- a/test/performanceTest.js
+++ b/test/performanceTest.js
@@ -1,4 +1,4 @@
-
+/* globals canvasAPI */
 const createLog = function(){
 	"use strict";
 	
@@ -85,28 +85,6 @@ const performTest = function(){
 	};
 }();
 
-function draw(canvas){
-	"use strict";
-	
-	canvas.setAttribute("width", 220);
-	canvas.setAttribute("height", 30);
-	
-	const fp_text = "BrowserLeaks,com <canvas> 10";
-	
-	const ctx = canvas.getContext("2d");
-	ctx.textBaseline = "top";
-	ctx.font = "14px 'Arial'";
-	ctx.textBaseline = "alphabetic";
-	ctx.fillStyle = "#f60";
-	ctx.fillRect(125, 1, 62, 20);
-	ctx.fillStyle = "#069";
-	ctx.fillText(fp_text, 2, 15);
-	ctx.fillStyle = "rgba(102, 204, 0, 07)";
-	ctx.fillText(fp_text, 4, 17);
-	
-	return ctx;
-}
-
 const fingerprintTest = function(){
 	"use strict";
 	
@@ -116,7 +94,7 @@ const fingerprintTest = function(){
 			// create window canvas
 			canvas = document.createElement("canvas");
 			// draw image in window canvas
-			draw(canvas);
+			canvasAPI.draw(canvas);
 		},
 		test: function fingerprintTest(){
 			return canvas.toDataURL();
diff --git a/test/settingsLoading.php b/test/settingsLoading.php
index a8eb380..e473aba 100644
--- a/test/settingsLoading.php
+++ b/test/settingsLoading.php
@@ -5,45 +5,16 @@
 	<meta http-equiv="content-type" content="text/html; charset=UTF-8">
 	<link href="testIcon.svg" type="image/png" rel="icon">
 	<link href="testIcon.svg" type="image/png" rel="shortcut icon">
+	<?php
+		echo "<script>" . file_get_contents("testAPI.js");
+		echo file_get_contents("canvasAPI.js") . "</script>";
+	?>
 	<script>
 		const firstDescriptor = Object.getOwnPropertyDescriptor(HTMLCanvasElement.prototype, "getContext");
 		console.log(new Date(), "starting first fingerprint", window.name);
-		function fingerPrint(){
-			"use strict";const canvas = document.createElement("canvas");
-			canvas.setAttribute("width", 220);
-			canvas.setAttribute("height", 30);
-			
-			const fp_text = "BrowserLeaks,com <canvas> 10";
-			
-			const ctx = canvas.getContext("2d");
-			ctx.textBaseline = "top";
-			ctx.font = "14px 'Arial'";
-			ctx.textBaseline = "alphabetic";
-			ctx.fillStyle = "#f60";
-			ctx.fillRect(125, 1, 62, 20);
-			ctx.fillStyle = "#069";
-			ctx.fillText(fp_text, 2, 15);
-			ctx.fillStyle = "rgba(102, 204, 0, 07)";
-			ctx.fillText(fp_text, 4, 17);
-			
-			return canvas.toDataURL();
-		}
-		async function hash(url){
-			"use strict";
-			
-			const buffer = new TextEncoder("utf-8").encode(url);
-			const hash = await crypto.subtle.digest("SHA-256", buffer);
-			const chunks = [];
-			(new Uint32Array(hash)).forEach(function(num){
-				chunks.push(num.toString(16));
-			});
-			return chunks.map(function(chunk){
-				return "0".repeat(8 - chunk.length) + chunk;
-			}).join("");
-		}
 		let firstFingerprint = false;
 		try {
-			firstFingerprint = fingerPrint();
+			firstFingerprint = canvasAPI.fingerprint().url;
 		}
 		catch (error){
 			console.log(new Date(), error);
@@ -94,14 +65,14 @@
 					output.classList.add("nok");
 				}
 				output.appendChild(document.createElement("br"));
-				const secondFingerprint = fingerPrint();
+				const secondFingerprint = canvasAPI.fingerprint().url;
 				if (firstFingerprint === secondFingerprint){
-					const firstHash = await hash(firstFingerprint);
+					const firstHash = await testAPI.hash(firstFingerprint);
 					output.appendChild(document.createTextNode("fingerprint consistent (" + firstHash + ") -> good!"));
 					output.classList.add("ok");
 				}
 				else {
-					const hashes = await Promise.all([hash(firstFingerprint), hash(secondFingerprint)]);
+					const hashes = await Promise.all([testAPI.hash(firstFingerprint), testAPI.hash(secondFingerprint)]);
 					output.appendChild(
 						document.createTextNode(
 							"fingerprint not consistent (" +
diff --git a/test/test.html b/test/test.html
index 5c4ae15..49cb2d8 100644
--- a/test/test.html
+++ b/test/test.html
@@ -71,5 +71,7 @@
 	Hash: <span class="hash"><i>click anywhere to populate</i></span> (isPointInPath: <span class="isPointInPath"></span>)
 	<button>refresh</button>
 </div>
+<script src="testAPI.js"></script>
+<script src="canvasAPI.js"></script>
 <script src="test.js"></script>
 </body></html>
\ No newline at end of file
diff --git a/test/test.js b/test/test.js
index ec2a434..91aba09 100644
--- a/test/test.js
+++ b/test/test.js
@@ -1,165 +1,72 @@
+/* globals testAPI, canvasAPI */
 (function(){
 	"use strict";
 	
-	function hashToString(hash){
-		const chunks = [];
-		(new Uint32Array(hash)).forEach(function(num){
-			chunks.push(num.toString(16));
-		});
-		return chunks.map(function(chunk){
-			return "0".repeat(8 - chunk.length) + chunk;
-		}).join("");
-	}
-	
 	async function show(container, {url, imageData, isPointInPath}){
 		const display = container.querySelector(".display");
 		display.src = url;
 		display.title = url;
-		const buffer = new TextEncoder("utf-8").encode(url);
 		const hashes = await Promise.all([
-			crypto.subtle.digest("SHA-256", buffer),
-			crypto.subtle.digest("SHA-256", imageData.data)
+			testAPI.hash(url),
+			testAPI.hash(imageData.data)
 		]);
 		container.querySelector(".hash").textContent =
-			hashToString(hashes[0]) + " / " +
-			hashToString(hashes[1]);
+			hashes[0] + " / " +
+			hashes[1];
 		container.querySelector(".isPointInPath").textContent = isPointInPath;
 	}
 	
-	if (location.search !== "?notInitial"){
-		try {show(document.getElementById("top"), topTest());}
-		catch (error){console.error(error);}
-		try {show(document.getElementById("iframe"), iframeTest(document.querySelector("#iframe iframe")));}
-		catch (error){console.error(error);}
-		try {show(document.getElementById("iframe2"), iframeTest(document.querySelector("#iframe2 iframe")));}
-		catch (error){console.error(error);}
-		try {show(document.getElementById("iframe3"), iframeTest(document.querySelector("#iframe3 iframe")));}
-		catch (error){console.error(error);}
-		try {show(document.getElementById("iframe4"), dynamicIframeTest1());}
-		catch (error){console.error(error);}
-		try {show(document.getElementById("iframe5"), dynamicIframeTest2());}
-		catch (error){console.error(error);}
-		try {show(document.getElementById("iframe6"), dynamicIframeTest3());}
-		catch (error){console.error(error);}
-		window.addEventListener("click", function windowOpenTest(){
-			window.removeEventListener("click", windowOpenTest);
-			const newWindow = window.open("/");
-			try{
-				show(document.getElementById("windowOpen"), copyToDifferentDocumentTest(newWindow.document));
-			}
-			catch (error){
-				console.error(error);
-			}
-			newWindow.close();
-		});
+	function iframeTest(testNode){
+		const iframe = testNode.querySelector("iframe");
+		return canvasAPI.fingerprint(iframe.contentWindow);
 	}
-	document.querySelector("#top button").addEventListener("click", function(){
-		show(document.getElementById("top"), topTest());
-	});
-	document.querySelector("#iframe button").addEventListener("click", function(){
-		show(document.getElementById("iframe"), iframeTest(document.querySelector("#iframe iframe")));
-	});
-	document.querySelector("#iframe2 button").addEventListener("click", function(){
-		show(document.getElementById("iframe2"), iframeTest(document.querySelector("#iframe2 iframe")));
-	});
-	document.querySelector("#iframe3 button").addEventListener("click", function(){
-		show(document.getElementById("iframe3"), iframeTest(document.querySelector("#iframe3 iframe")));
-	});
-	document.querySelector("#iframe4 button").addEventListener("click", function(){
-		show(document.getElementById("iframe4"), dynamicIframeTest1());
-	});
-	document.querySelector("#iframe5 button").addEventListener("click", function(){
-		show(document.getElementById("iframe5"), dynamicIframeTest2());
-	});
-	document.querySelector("#iframe6 button").addEventListener("click", function(){
-		show(document.getElementById("iframe6"), dynamicIframeTest3());
-	});
-	document.querySelector("#windowOpen button").addEventListener("click", function(){
-		const newWindow = window.open("/");
-		show(document.getElementById("windowOpen"), copyToDifferentDocumentTest(newWindow.document));
-		newWindow.close();
+	
+	const tests = {
+		top: function(){return canvasAPI.fingerprint();},
+		iframe: iframeTest,
+		iframe2: iframeTest,
+		iframe3: iframeTest,
+		iframe4: dynamicIframeTest1,
+		iframe5: dynamicIframeTest2,
+		iframe6: dynamicIframeTest3,
+		windowOpen: async function(testNode, initial){
+			if (initial){
+				return new Promise(function(resolve){
+					window.addEventListener("click", function windowOpenTest(){
+						window.removeEventListener("click", windowOpenTest);
+						const newWindow = window.open("/");
+						try{
+							resolve(canvasAPI.fingerprint(newWindow));
+						}
+						catch (error){
+							console.error(error);
+						}
+						newWindow.close();
+					});
+				});
+			}
+			else {
+				const newWindow = window.open("/");
+				const fingerprint = canvasAPI.fingerprint(newWindow);
+				newWindow.close();
+				return fingerprint;
+			}
+		}
+	};
+	
+	Object.keys(tests).forEach(async function(testName){
+		const testNode = document.getElementById(testName);
+		const callback = tests[testName];
+		if (location.search !== "?notInitial"){
+			try {show(testNode, await callback(testNode, true));}
+			catch (error){console.error(testName, error);}
+		}
+		testNode.querySelector("button").addEventListener("click", async function(){
+			show(testNode, await callback(testNode));
+		});
 	});
 }());
 
-function draw(canvas){
-	"use strict";
-	
-	canvas.setAttribute("width", 220);
-	canvas.setAttribute("height", 30);
-	
-	const fp_text = "BrowserLeaks,com <canvas> 10";
-	
-	const ctx = canvas.getContext("2d");
-	ctx.textBaseline = "top";
-	ctx.font = "14px 'Arial'";
-	ctx.textBaseline = "alphabetic";
-	ctx.fillStyle = "#f60";
-	ctx.fillRect(125, 1, 62, 20);
-	ctx.fillStyle = "#069";
-	ctx.fillText(fp_text, 2, 15);
-	ctx.fillStyle = "rgba(102, 204, 0, 07)";
-	ctx.fillText(fp_text, 4, 17);
-	
-	return ctx;
-}
-
-function getIsPointInPath(ctx){
-	"use strict";
-	ctx.beginPath();
-	ctx.moveTo(20, 19);
-	ctx.lineTo(40, 19);
-	ctx.lineTo(30, 30);
-	ctx.closePath();
-	ctx.stroke();
-	
-	return ctx.isPointInPath(30, 19);
-}
-
-function topTest(){
-	"use strict";
-	
-	// create window canvas
-	const canvas = document.createElement("canvas");
-	// draw image in window canvas
-	const ctx = draw(canvas);
-	return {
-		imageData: ctx.getImageData(0, 0, canvas.width, canvas.height),
-		url: canvas.toDataURL(),
-		isPointInPath: getIsPointInPath(ctx)
-	};
-}
-
-function copyToDifferentDocumentTest(otherDocument){
-	"use strict";
-
-	// create window canvas
-	const canvas = document.createElement("canvas");
-
-	// draw image in window canvas
-	draw(canvas);
-
-	// create other canvas and context
-	const otherCanvas = otherDocument.createElement("canvas");
-	otherCanvas.setAttribute("width", 220);
-	otherCanvas.setAttribute("height", 30);
-	const otherContext = otherCanvas.getContext("2d");
-
-	// copy image from window canvas to iframe context
-	otherContext.drawImage(canvas, 0, 0);
-
-	return {
-		imageData: otherContext.getImageData(0, 0, otherCanvas.width, otherCanvas.height),
-		url: otherCanvas.toDataURL(),
-		isPointInPath: getIsPointInPath(otherContext)
-	};
-}
-
-function iframeTest(iframe){
-	"use strict";
-	
-	return copyToDifferentDocumentTest(iframe.contentDocument);
-}
-
 function dynamicIframeTest1(){
 	"use strict";
 	
@@ -168,7 +75,7 @@ function dynamicIframeTest1(){
 	document.body.appendChild(iframe);
 	const iframeWindow = frames[length];
 	document.body.removeChild(iframe);
-	return copyToDifferentDocumentTest(iframeWindow.document);
+	return canvasAPI.fingerprint(iframeWindow);
 }
 
 function dynamicIframeTest2(){
@@ -179,7 +86,7 @@ function dynamicIframeTest2(){
 	document.body.appendChild(iframe);
 	const iframeWindow = window[length];
 	document.body.removeChild(iframe);
-	return copyToDifferentDocumentTest(iframeWindow.document);
+	return canvasAPI.fingerprint(iframeWindow);
 }
 
 function dynamicIframeTest3(){
@@ -191,5 +98,5 @@ function dynamicIframeTest3(){
 	div.innerHTML = "<iframe></iframe>";
 	const iframeWindow = window[length];
 	document.body.removeChild(div);
-	return copyToDifferentDocumentTest(iframeWindow.document);
+	return canvasAPI.fingerprint(iframeWindow);
 }
\ No newline at end of file
diff --git a/test/testAPI.js b/test/testAPI.js
new file mode 100644
index 0000000..e655c32
--- /dev/null
+++ b/test/testAPI.js
@@ -0,0 +1,25 @@
+const testAPI = function(){
+	"use strict";
+	
+	function bufferToString(hash){
+		const chunks = [];
+		(new Uint32Array(hash)).forEach(function(num){
+			chunks.push(num.toString(16));
+		});
+		return chunks.map(function(chunk){
+			return "0".repeat(8 - chunk.length) + chunk;
+		}).join("");
+	}
+	
+	
+	
+	return {
+		hash: async function(input){
+			const buffer = ((typeof input) === "string")?
+				new TextEncoder("utf-8").encode(input):
+				input;
+			const hash = await crypto.subtle.digest("SHA-256", buffer);
+			return bufferToString(hash);
+		}
+	};
+}();
\ No newline at end of file