Add failure scenarios tests for connection, appendToStream, deleteStream (wip)

src/common/log/fileLogger.js

@@ -0,0 +1,39 @@
+var util = require('util');
+var fs = require('fs');
+var os = require('os');
+
+function FileLogger(filePath, append) {
+  this._filePath = filePath;
+  if (!append) {
+    try {
+      fs.unlink(filePath);
+    } catch(e) {}
+  }
+}
+
+function createLine(level, args, argsStartIndex) {
+  var msg = util.format.apply(util, Array.prototype.slice.call(args, argsStartIndex));
+  return util.format('%s %s - %s%s', new Date().toISOString(), level, msg, os.EOL);
+}
+
+FileLogger.prototype.debug = function() {
+  var line = createLine('DEBUG', arguments, 0);
+  fs.appendFileSync(this._filePath, line);
+};
+
+FileLogger.prototype.info = function() {
+  var line = createLine('INFO', arguments, 0);
+  fs.appendFileSync(this._filePath, line);
+};
+
+FileLogger.prototype.error = function(e) {
+  var hasError = e instanceof Error;
+  var line = createLine('ERROR', arguments, hasError ? 1 : 0);
+  if (hasError) {
+    line += e.stack + os.EOL;
+  }
+  fs.appendFileSync(this._filePath, line);
+};
+
+
+module.exports = FileLogger;