[Testing] Travis testing devices updates. (material-components#1595)

* [Testing] Updating test_all for multiple devices.

* [Testing] Setting Travis device matrix to use a 32-bit device.

* [Testing] Comments in Travis file.

* [Testing] Bumping Travis testing 'latest' version to 10.3.

* [Testing] Correcting Travis device target.

.travis.yml

@@ -19,8 +19,10 @@ env:
   - LC_CTYPE=en_US.UTF-8
   - LANG=en_US.UTF-8
   matrix:
-    - DESTINATION="platform=iOS Simulator,name=iPhone 7,OS=10.2" SDK="iphonesimulator10.2"
-    - DESTINATION="platform=iOS Simulator,name=iPhone 5s,OS=8.1" SDK="iphonesimulator8.1"
+    - DESTINATION="platform=iOS Simulator,name=iPhone 7,OS=10.3.1" SDK="iphonesimulator10.3.1"
+    # The iPhone 5 was chosen because it is a 32-bit device.
+    # 8.1 was chosen because it is the earliest iOS offered here.
+    - DESTINATION="platform=iOS Simulator,name=iPhone 5,OS=8.1" SDK="iphonesimulator8.1"
 
 before_install:
   - gem install xcpretty --no-rdoc --no-ri --no-document --quiet

scripts/test_all

@@ -16,9 +16,13 @@
 
 readonly SCRIPTS_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 readonly ROOT_DIR="$(dirname $SCRIPTS_DIR)"
-readonly DESTINATION="platform=iOS Simulator,name=iPhone 7,OS=latest"
 readonly COVERAGE_OPTIONS="GCC_INSTRUMENT_PROGRAM_FLOW_ARCS=YES GCC_GENERATE_TEST_COVERAGE_FILES=YES -enableCodeCoverage YES"
 
+# When run on Travis CI, this variable should be passed in
+if [[ ! $DESTINATION ]]; then
+  DESTINATION="platform=iOS Simulator,name=iPhone 7,OS=latest"
+fi
+
 # Given a path to an Xcode log file in $1, print a guess at what caused the
 # failure.
 function guess_failure() {
@@ -36,7 +40,7 @@ else
 fi
 
 all_tests_ok=1
-for workspace_scheme in $WORKSPACE_SCHEMES; do  
+for workspace_scheme in $WORKSPACE_SCHEMES; do
   workspace=$(echo $workspace_scheme | cut -d: -f1)
   scheme=$(echo $workspace_scheme | cut -d: -f2)
 
@@ -60,7 +64,7 @@ for workspace_scheme in $WORKSPACE_SCHEMES; do
   fi
 done
 
-# If any test failed, exit with a failure exit status so continuous integration 
+# If any test failed, exit with a failure exit status so continuous integration
 # tools can react appropriately.
 if [ "$all_tests_ok" -eq 1 ]; then
   exit 0