Restructured library.

lib/doctest.js

@@ -0,0 +1,113 @@
+// Allows browsers to perform doctests.
+// Uses the code highlight package from http://highlightjs.readthedocs.io
+// if available
+
+var docTestLogMessages = []
+
+Array.prototype.equals = function(array) {
+    return this.length == array.length &&
+         this.every( function(this_i,i) { return this_i == array[i] } )
+}
+
+export default class Doctest {
+
+    static assert(value) {
+        if (!value) {
+            throw new Error('Assertion violated')
+        }
+    }
+
+    static pprint(obj) {
+        if (obj === null)
+            return 'null'
+        let stringified = obj.toString()
+        if (stringified == '[object Object]')
+            return JSON.stringify(obj)
+        return stringified
+    }
+
+    static expect(expr, value) {
+        if (this.pprint(expr) != this.pprint(value)) {
+            //throw new Error("got `" + expr + "` but expected `" + value + "`.")
+            throw new Error('got `' + this.pprint(expr) + '` but expected `' + this.pprint(value) + '`.')
+        }
+    }
+
+    static expectError(error, message) {
+        let index = error.toString().indexOf(message)
+        if (index < 0) {
+            throw new Error('got `' + message + '` but expected `' + error + '`.')
+        }
+    }
+
+    static expectLog(...messages) {
+       // if (!docTestLogMessages.equals(messages)) {
+            docTestLogMessages.forEach((msg, i) => {
+                if (msg != messages[i])
+                    throw new Error('Unexpected log message: `' + messages[i] + '`.')
+            })
+        //    throw new Error('Uups')
+        //}
+    }
+
+    static log(message) {
+        docTestLogMessages.push(message)
+    }
+
+    static highlight(code) {
+        if (typeof(hljs) == 'undefined')
+            return code
+        return hljs.highlight('javascript', code)
+    }
+
+    static stripLeadingLines(code) {
+        let result = []
+        let informative = false
+        for(let line of code.split('\n')) {
+            if (line.trim().length > 0) {
+                informative = true
+            }
+            if (informative)
+                result.push(line)
+        }
+        return result.join('\n')
+    }
+
+    static event(type='mouse', {clientX = 0, clientY = 0} = {}) {
+        if (type.startsWith('mouse')) {
+            return new MouseEvent(type, { clientX, clientY })
+        }
+        return { type, clientX, clientY }
+    }
+
+    static run(replaceExpect=false) {
+        if (typeof(hljs) != 'undefined') {
+            hljs.initHighlighting()
+        }
+        let doctests = document.querySelectorAll('.doctest')
+        for(let i=0; i<doctests.length; i++) {
+            let doctest = doctests[i]
+            let code = this.stripLeadingLines(doctest.innerHTML)
+            let text = this.highlight(code)
+            let pre = document.createElement('pre')
+            // See http://stackoverflow.com/questions/1068280/javascript-regex-multiline-flag-doesnt-work
+            // let re = /Doctest\.expect\(([\s\S]*)[\,\s\S]*([\s\S]*)\)/g
+            let lines = text.value.split('\n')
+            let better = []
+            for(let line of lines) {
+                if (replaceExpect && line.trim().startsWith('Doctest.expect(')) {
+                    line = line.replace(/Doctest\.expect\(/, '>>> ').trim()
+                    if (line.endsWith(')') || line.endsWith(',')) {
+                        line = line.slice(0, -1)
+                    }
+                }
+                better.push(line)
+            }
+            pre.innerHTML = better.join('\n') // text.value.replace(re, ">>> $1\n$2")
+            doctest.parentNode.replaceChild(pre, doctest)
+        }
+    }
+}
+
+// Needed to make Doctest visible in modules
+//window.Doctest = Doctest