fix pre-launch bug (fix #1772)

and add tests

lib/appium.js

@@ -122,6 +122,19 @@ Appium.prototype.getDeviceType = function(desiredCaps) {
   throw new Error(errMsg);
 };
 
+Appium.prototype.getDeviceTypeFromApp = function(app) {
+  if (this.args.ipa) {
+    return "ios";
+  } else if (this.args.androidPackage || this.args.avd) {
+    return "android";
+  } else if (/\.app/.test(app)) {
+    return "ios";
+  } else if (/\.apk/.test(app)) {
+    return "android";
+  }
+  throw new Error("Could not determine your device type from --app");
+};
+
 Appium.prototype.isMockIos = function() {
   return this.deviceType === "mock_ios";
 };
@@ -176,9 +189,13 @@ Appium.prototype.configure = function(desiredCaps, cb) {
     app = desiredCaps.app;
   }
   try {
-    this.deviceType = this.getDeviceType(desiredCaps);
+    if (this.args.launch) {
+      this.deviceType = this.getDeviceTypeFromApp(this.args.app);
+    } else {
+      this.deviceType = this.getDeviceType(desiredCaps);
+    }
   } catch (e) {
-    logger.error(e);
+    logger.error(e.message);
     return cb(e);
   }
   if (this.isMockIos()) {

test/functional/appium/prelaunch.js

@@ -0,0 +1,53 @@
+"use strict";
+var path = require('path')
+  , iosApp = path.resolve(__dirname, "..", "..", "..", "sample-code", "apps",
+      "TestApp", "build", "Release-iphonesimulator", "TestApp.app")
+  , androidApp = path.resolve(__dirname, "..", "..", "..", "sample-code",
+      "apps", "ApiDemos", "bin", "ApiDemos-debug.apk")
+  , spawn = require('child_process').spawn
+  , crazyPort = 4799;
+
+var waitForLaunch = function(app, extraArgs, cb) {
+  var args = [".", "-p", crazyPort, "-l", "-dd", "-m", "--app", app];
+  args = args.concat(extraArgs);
+  var proc = spawn('node', args, {cwd: path.resolve(__dirname, "..", "..", "..")});
+  proc.stdout.setEncoding('utf8');
+  proc.stderr.setEncoding('utf8');
+  var calledBack = false;
+  var output = '';
+  var tm = setTimeout(function() {
+    calledBack = true;
+    proc.kill();
+    cb(new Error("Appium never started. Output was: " + output));
+  }, 30000);
+  proc.stdout.on('data', function(data) {
+    output += data;
+    if (!calledBack &&/Appium REST http interface listener started on/.test(data)) {
+      clearTimeout(tm);
+      proc.kill();
+      calledBack = true;
+      cb();
+    }
+  });
+  proc.stderr.on('data', function(data) {
+    output += data;
+  });
+  proc.on('exit', function() {
+    if (!calledBack) {
+      calledBack = true;
+      cb(new Error("Appium never started. Output was: " + output));
+    }
+  });
+};
+
+describe('Pre-launching apps', function() {
+  it('should work for ios', function(done) {
+    waitForLaunch(iosApp, [], done);
+  });
+
+  it('should work for android', function(done) {
+    var args = ["--app-pkg", "com.example.android.apis", "--app-activity",
+      ".ApiDemos"];
+    waitForLaunch(androidApp, args, done);
+  });
+});