add xcpretty

.travis.yml

   - source ./scripts/env/installAndroidSDK.sh
         # AppleSimUtils
   - source ./scripts/env/installAppleSimUtils.sh
+        # xcpretty
+  - source ./scripts/env/installXcpretty.sh
 
 script:
   - set -e

scripts/env/installXcpretty.sh

+#!/bin/bash -e
+
+gem install xcpretty

scripts/test.e2e.ios.js

   const scheme = release ? `playground_release` : `playground`;
   const conf = release ? `Release` : `Debug`;
 
-  exec.execSync(`cd ./playground/ios &&
+  execWithXcprettyIfPossible(`cd ./playground/ios &&
             RCT_NO_LAUNCH_PACKAGER=true
             xcodebuild build
             -scheme ${scheme}
   e2e();
 }
 
+function execWithXcprettyIfPossible(cmd) {
+  if (exec.which('xcpretty')) {
+    exec.execSync(`${cmd} | xcpretty`);
+  } else {
+    exec.execSync(cmd);
+  }
+}
+
 run();

scripts/test.unit.ios.js

 function run() {
   const conf = release ? `Release` : `Debug`;
 
-  exec.execSync(`cd ./playground/ios &&
+  execWithXcprettyIfPossible(`cd ./playground/ios &&
             RCT_NO_LAUNCH_PACKAGER=true
             xcodebuild build build-for-testing
             -scheme "ReactNativeNavigation"
             -derivedDataPath ./DerivedData/playground
             ONLY_ACTIVE_ARCH=YES`);
 
-  exec.execSync(`cd ./playground/ios &&
+  execWithXcprettyIfPossible(`cd ./playground/ios &&
             RCT_NO_LAUNCH_PACKAGER=true
             xcodebuild test-without-building
             -scheme "ReactNativeNavigation"
             ONLY_ACTIVE_ARCH=YES`);
 }
 
+function execWithXcprettyIfPossible(cmd) {
+  if (exec.which('xcpretty')) {
+    exec.execSync(`${cmd} | xcpretty`);
+  } else {
+    exec.execSync(cmd);
+  }
+}
+
 run();