Improve bin/test with more functionality

`bin/test` now supports flags to customize the behavior. We can use this
immediately for Circle by outputting JUnit xml that Circle can use to
get some insight into our test suite.

bin/test

@@ -1,31 +1,65 @@
-#!/usr/bin/env sh
+#!/bin/bash
+#
+# Runs tests via xcodebuild, formatting results with xcpretty.
+#
+# Usage: bin/test [options]
+#
+# Options:
+#   -k    Clean before running the tests.
+#   -r    Emit JUnit XML report.
+#   -t    Use RSpec-style test output.
 
-set -o pipefail
+set -eo pipefail
+
+build_actions=(test)
+test_reports_dir="${CIRCLE_TEST_REPORTS:-build}"
+xcpretty_options=(--color)
+
+while getopts krt opt; do
+  case ${opt} in
+    k)
+      build_actions=(clean test)
+      ;;
+    r)
+      xcpretty_options+=(--report junit --output "${test_reports_dir}/test-report.xml")
+      ;;
+    t)
+      xcpretty_options+=(--test)
+      ;;
+    *)
+      exit 1
+      ;;
+  esac
+done
+
+shift $((OPTIND - 1))
+
+mkdir -p "${test_reports_dir}"
 
 xcrun xcodebuild \
   -workspace Argo.xcworkspace \
   -scheme Argo-Mac \
-  test \
-  | xcpretty --color
+  "${build_actions[@]}" \
+  | xcpretty "${xcpretty_options[@]}"
 
 xcrun xcodebuild \
   -workspace Argo.xcworkspace \
   -scheme Argo-iOS \
   -destination "platform=iOS Simulator,name=iPhone 6" \
-  test \
-  | xcpretty --color
+  "${build_actions[@]}" \
+  | xcpretty "${xcpretty_options[@]}"
 
 xcrun xcodebuild \
   -workspace Argo.xcworkspace \
   -scheme Argo-watchOS \
   -destination "generic/platform=watchOS" \
   CODE_SIGNING_REQUIRED=NO \
   CODE_SIGN_IDENTITY="" \
-  | xcpretty --color
+  | xcpretty "${xcpretty_options[@]}"
 
 xcrun xcodebuild \
   -workspace Argo.xcworkspace \
   -scheme Argo-tvOS \
   -destination "platform=tvOS Simulator,name=Apple TV 1080p" \
-  test \
-  | xcpretty --color
+  "${build_actions[@]}" \
+  | xcpretty "${xcpretty_options[@]}"

circle.yml

@@ -8,4 +8,4 @@ dependencies:
 
 test:
   override:
-    - bin/test
+    - bin/test -r