Added test for SVG

For #589 and #590

lib/modifiedSVGAPI.js

@@ -0,0 +1,88 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+ (function(){
+	"use strict";
+	
+	let scope;
+	if ((typeof exports) !== "undefined"){
+		scope = exports;
+	}
+	else {
+		scope = require.register("./modifiedSVGAPI", {});
+	}
+	
+	const {checkerWrapper, setProperties, getStatusByFlag} = require("./modifiedAPIFunctions");
+	const {byteArrayToString: hash} = require("./hash");
+	
+	
+	let randomSupply = null;
+	scope.setRandomSupply = function(supply){
+		randomSupply = supply;
+	};
+	
+	function getValueHash(value){
+		return hash(new Float32Array([value]));
+	}
+	
+	const cache = {};
+	function getFakeValue(value, window){
+		const valueHash = getValueHash(value);
+		let cachedValue = cache[valueHash];
+		if (typeof cachedValue === "number"){
+			return cachedValue;
+		}
+		else {
+			const rng = randomSupply.getRng(1, window);
+			const fakedValue = value + 0.01 * (rng(0) / 0xffffffff - 0.5);
+			const fakedHash = getValueHash(fakedValue);
+			cache[valueHash] = fakedValue;
+			cache[fakedHash] = fakedValue;
+			return fakedValue;
+		}
+	}
+	scope.getFakeValue = getFakeValue;
+	
+	function getFakeValueCallback(args, check){
+		const {notify, window, original} = check;
+		const ret = args.length? original.call(this, ...args): original.call(this);
+		notify("fakedSVGReadout");
+		return getFakeValue(ret, window);
+	}
+	
+	scope.changedFunctions = {
+		getTotalLength: {
+			object: ["SVGGeometryElement"],
+			fakeGenerator: function(checker){
+				return function getTotalLength(){
+					return checkerWrapper(checker, this, arguments, getFakeValueCallback);
+				};
+			}
+		},
+		getComputedTextLength: {
+			object: ["SVGTextContentElement"],
+			fakeGenerator: function(checker){
+				return function getComputedTextLength(){
+					return checkerWrapper(checker, this, arguments, getFakeValueCallback);
+				};
+			}
+		},
+		getSubStringLength: {
+			object: ["SVGTextContentElement"],
+			fakeGenerator: function(checker){
+				return function getSubStringLength(charnum, nchars){
+					return checkerWrapper(checker, this, arguments, getFakeValueCallback);
+				};
+			}
+		},
+	};
+	
+	
+	scope.changedGetters = [];
+	
+	setProperties(scope.changedFunctions, scope.changedGetters, {
+		type: "readout",
+		getStatus: getStatusByFlag("protectSVG"),
+		api: "svg"
+	});
+}());