test: add --shards option to mobile e2e tests

.maestro/scripts/run-tests.sh

@@ -1,21 +1,24 @@
 #!/bin/bash
-# run-tests.sh - set up a device, build the example app, and run Maestro flows.
+# run-tests.sh - set up devices, build the example app, and run Maestro flows.
 #
 # Usage:
-#   ./run-tests.sh --platform <ios|android> [--update-screenshots] [--rebuild] [flow ...]
+#   ./run-tests.sh --platform <ios|android> [--update-screenshots] [--rebuild] [--shards N] [flow ...]
 #
 # Options:
 #   --platform            Required. Target platform: ios or android.
 #   --update-screenshots  Refresh baselines.
 #   --rebuild             Force a rebuild and install, even if the app is
 #                         already installed on the device.
+#   --shards N            Number of devices to boot and split flows across
+#                         (default 1). Automatically clamped to the number of
+#                         flows being run.
 #   flow ...              One or more Maestro flow files or directories to run.
 #                         Defaults to all component suites if omitted.
 #
 # Examples:
 #   ./run-tests.sh --platform ios
 #   ./run-tests.sh --platform android --update-screenshots .maestro/enrichedInput/flows/core_controls_smoke.yaml
-#   ./run-tests.sh --platform ios --rebuild
+#   ./run-tests.sh --platform ios --rebuild --shards 2
 
 set -euo pipefail
 
@@ -38,21 +41,29 @@ REPO_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
 MAESTRO_ROOT="$REPO_ROOT/.maestro"
 SCREENSHOT_ROOT="$MAESTRO_ROOT"
 BUNDLE_ID="swmansion.enriched.example"
+EXAMPLE_DIR="$REPO_ROOT/apps/example"
 
 PLATFORM=""
 UPDATE_SCREENSHOTS=""
 REBUILD=""
+SHARDS=1
 FLOWS=""
 
 while [ $# -gt 0 ]; do
   case "$1" in
     --platform)           PLATFORM="$2"; shift 2 ;;
     --update-screenshots) UPDATE_SCREENSHOTS="true"; shift ;;
     --rebuild)            REBUILD="true"; shift ;;
+    --shards)             SHARDS="$2"; shift 2 ;;
     *)                    FLOWS="${FLOWS:+$FLOWS }$1"; shift ;;
   esac
 done
 
+if ! [[ "$SHARDS" =~ ^[0-9]+$ ]]; then
+  echo "Error: --shards requires a numeric integer. Received: '$SHARDS'" >&2
+  exit 1
+fi
+
 [ -z "$FLOWS" ] && FLOWS=".maestro/enrichedInput/flows .maestro/enrichedText/flows"
 
 case "$PLATFORM" in
@@ -61,47 +72,135 @@ case "$PLATFORM" in
   *)       echo "Error: --platform must be ios or android" >&2; exit 1 ;;
 esac
 
-DEVICE_ID=$("$SETUP" | tee /dev/tty | grep "^DEVICE_ID=" | cut -d= -f2)
+# No point booting more devices than there are flows to run
+# (e.g. when running a single flow file).
+FLOW_COUNT=0
+for f in $FLOWS; do
+  if [ -d "$f" ]; then
+    n=$(find "$f" -name '*.yaml' | wc -l | tr -d ' ')
+  elif [ -f "$f" ]; then
+    n=1
+  else
+    n=0
+  fi
+  FLOW_COUNT=$((FLOW_COUNT + n))
+done
+if [ "$FLOW_COUNT" -gt 0 ] && [ "$SHARDS" -gt "$FLOW_COUNT" ]; then
+  SHARDS=$FLOW_COUNT
+fi
+[ "$SHARDS" -lt 1 ] && SHARDS=1
+
+# Stream setup progress to the terminal; fall back to stderr when
+# no TTY is attached (e.g. CI).
+TTY_OUT=/dev/tty
+( : > /dev/tty ) 2>/dev/null || TTY_OUT=/dev/stderr
+
+DEVICE_IDS_CSV=$("$SETUP" "$SHARDS" | tee "$TTY_OUT" | grep "^DEVICE_IDS=" | cut -d= -f2)
+if [ -z "$DEVICE_IDS_CSV" ]; then
+  echo "Error: setup script did not return any DEVICE_IDS" >&2
+  exit 1
+fi
+IFS=',' read -r -a DEVICES <<< "$DEVICE_IDS_CSV"
+DEVICE_ID="${DEVICES[0]}"
 
 app_installed() {
+  local dev="$1"
   if [ "$PLATFORM" = ios ]; then
-    xcrun simctl listapps "$DEVICE_ID" 2>/dev/null | grep -q "$BUNDLE_ID"
+    xcrun simctl listapps "$dev" 2>/dev/null | grep -q "$BUNDLE_ID"
   else
-    adb -s "$DEVICE_ID" shell pm list packages "$BUNDLE_ID" 2>/dev/null | grep -q "$BUNDLE_ID"
+    adb -s "$dev" shell pm list packages "$BUNDLE_ID" 2>/dev/null | grep -q "$BUNDLE_ID"
   fi
 }
 
-# Adjusts the system's text-size setting.
+# Adjusts the system's text-size setting on every shard device.
 set_font_scale() {
+  local dev
   case "$1" in
     default) ios_size="large";               android_scale="1.0" ;;
     large)   ios_size="accessibility-large"; android_scale="1.5" ;;
     *) echo "set_font_scale: unknown size '$1'" >&2; return 1 ;;
   esac
-  if [ "$PLATFORM" = ios ]; then
-    xcrun simctl ui "$DEVICE_ID" content_size "$ios_size"
-  else
-    adb -s "$DEVICE_ID" shell settings put system font_scale "$android_scale"
-  fi
+  for dev in "${DEVICES[@]}"; do
+    if [ "$PLATFORM" = ios ]; then
+      xcrun simctl ui "$dev" content_size "$ios_size"
+    else
+      adb -s "$dev" shell settings put system font_scale "$android_scale"
+    fi
+  done
 }
 
 # Guarantees the font scale is restored on any exit.
 # Without this, the accessibility tests below would leave the device
 # in a scaled-up state.
 trap 'set_font_scale default' EXIT
 
-if [ -n "$REBUILD" ] || ! app_installed; then
-  [ -n "$REBUILD" ] && echo "=== rebuild requested, building and installing ==="
-  [ -z "$REBUILD" ] && echo "=== App ($BUNDLE_ID) not found, building and installing ==="
+# Builds and installs on the given device via the react-native CLI.
+build_and_install() {
+  local dev="$1"
+  if [ "$PLATFORM" = ios ]; then
+    yarn example ios --udid "$dev"
+  else
+    yarn example android --device "$dev"
+  fi
+}
+
+# Installs the already-built app artifact on the given device. Tries the
+# build output first, then the copy installed on the primary device, and
+# only falls back to a full build if neither exists.
+install_prebuilt() {
+  local dev="$1" app_path apk_path
   if [ "$PLATFORM" = ios ]; then
-    yarn example ios --udid "$DEVICE_ID"
+    app_path=$(ls -td "$EXAMPLE_DIR/ios/build/Build/Products/Debug-iphonesimulator"/*.app 2>/dev/null | head -1 || true)
+    if [ -z "$app_path" ]; then
+      app_path=$(xcrun simctl get_app_container "$DEVICE_ID" "$BUNDLE_ID" app 2>/dev/null || true)
+    fi
+    if [ -n "$app_path" ]; then
+      echo "=== Installing prebuilt app on $dev ==="
+      xcrun simctl install "$dev" "$app_path"
+    else
+      echo "warn: no prebuilt .app found, building for $dev" >&2
+      build_and_install "$dev"
+    fi
   else
-    yarn example android --device "$DEVICE_ID"
+    apk_path=$(ls -t "$EXAMPLE_DIR/android/app/build/outputs/apk/debug"/*.apk 2>/dev/null | head -1 || true)
+    if [ -z "$apk_path" ]; then
+      local device_apk
+      device_apk=$(adb -s "$DEVICE_ID" shell pm path "$BUNDLE_ID" 2>/dev/null | head -1 | cut -d: -f2 | tr -d '\r' || true)
+      if [ -n "$device_apk" ]; then
+        apk_path=$(mktemp -d)/example.apk
+        adb -s "$DEVICE_ID" pull "$device_apk" "$apk_path" >/dev/null
+      fi
+    fi
+    if [ -n "$apk_path" ]; then
+      echo "=== Installing prebuilt app on $dev ==="
+      adb -s "$dev" install -r "$apk_path"
+    else
+      echo "warn: no prebuilt .apk found, building for $dev" >&2
+      build_and_install "$dev"
+    fi
   fi
+}
+
+if [ -n "$REBUILD" ] || ! app_installed "$DEVICE_ID"; then
+  [ -n "$REBUILD" ] && echo "=== rebuild requested, building and installing ==="
+  [ -z "$REBUILD" ] && echo "=== App ($BUNDLE_ID) not found, building and installing ==="
+  build_and_install "$DEVICE_ID"
 else
-  echo "=== App ($BUNDLE_ID) already installed, skipping build ==="
+  echo "=== App ($BUNDLE_ID) already installed on $DEVICE_ID, skipping build ==="
 fi
 
+# Reuse the artifact built above for the remaining shard devices.
+i=1
+while [ "$i" -lt "${#DEVICES[@]}" ]; do
+  dev="${DEVICES[$i]}"
+  if [ -n "$REBUILD" ] || ! app_installed "$dev"; then
+    install_prebuilt "$dev"
+  else
+    echo "=== App ($BUNDLE_ID) already installed on $dev, skipping install ==="
+  fi
+  i=$((i + 1))
+done
+
 EXTRA="--env SCREENSHOT_ROOT=$SCREENSHOT_ROOT"
 [ -n "$UPDATE_SCREENSHOTS" ] && EXTRA="$EXTRA --env UPDATE_SCREENSHOTS=true"
 
@@ -111,6 +210,11 @@ case "$PLATFORM" in
   android) EXTRA="$EXTRA --exclude-tags ios-only" ;;
 esac
 
+# Split flows across all shard devices. With --shard-split each flow still
+# runs exactly once, so shared screenshot baselines stay safe.
+DEVICE_ARGS="--device $DEVICE_IDS_CSV"
+[ "$SHARDS" -gt 1 ] && DEVICE_ARGS="$DEVICE_ARGS --shard-split $SHARDS"
+
 # Maestro resolves addMedia paths by walking the workspace inputs. Since assets
 # live outside the flows directory, always include it so media files are found.
 ASSETS_DIR="$MAESTRO_ROOT/assets"
@@ -127,8 +231,11 @@ run_maestro() {
   local tmp rc
   tmp=$(mktemp)
   # `script` allocates a pseudo-TTY so maestro keeps
-  # ANSI colors when piped through `tee`.
-  if [[ "$OSTYPE" == darwin* ]]; then
+  # ANSI colors when piped through `tee`. It needs a real
+  # terminal though, so skip it when there is none (e.g. CI).
+  if ! [ -t 1 ]; then
+    maestro test "$@" 2>&1 | tee "$tmp"
+  elif [[ "$OSTYPE" == darwin* ]]; then
     script -q /dev/null maestro test "$@" 2>&1 | tee "$tmp"
   else
     local cmd
@@ -148,7 +255,7 @@ set +e
 
 echo "=== Running maestro tests ==="
 # shellcheck disable=SC2086
-run_maestro --device "$DEVICE_ID" --exclude-tags accessibility $EXTRA $FLOWS
+run_maestro $DEVICE_ARGS --exclude-tags accessibility $EXTRA $FLOWS
 EXIT_REGULAR=$?
 
 # These are the tests that require changing the system's settings
@@ -157,7 +264,7 @@ echo "=== Running maestro accessibility tests ==="
 set_font_scale large
 
 # shellcheck disable=SC2086
-run_maestro --device "$DEVICE_ID" --include-tags accessibility $EXTRA $FLOWS
+run_maestro $DEVICE_ARGS --include-tags accessibility $EXTRA $FLOWS
 EXIT_A11Y=$?
 
 set -e