one-line waiting for app start (#3411)

* one-line waiting for app start

* remove fixed todo

appveyor.yml

@@ -28,8 +28,6 @@ platform:
   - x64
 
 install:
-  # TODO: Remove after https://github.com/appveyor/ci/issues/1426 is fixed
-  - set PATH=C:\Program Files\Git\mingw64\bin;%PATH%
   - ps: Install-Product node $env:nodejs_version $env:platform
 
 build: off
@@ -41,4 +39,4 @@ skip_commits:
 test_script:
   - node --version
   - npm --version
-  - sh tasks/e2e-%test_suite%.sh
+  - bash tasks/e2e-%test_suite%.sh

tasks/e2e-kitchensink.sh

@@ -218,14 +218,7 @@ PORT=3001 \
   REACT_APP_SHELL_ENV_MESSAGE=fromtheshell \
   NODE_PATH=src \
   nohup npm start &>$tmp_server_log &
-while true
-do
-  if grep -q 'You can now view' $tmp_server_log; then
-    break
-  else
-    sleep 1
-  fi
-done
+grep -q 'You can now view' <(tail -f $tmp_server_log)
 E2E_URL="http://localhost:3001" \
   REACT_APP_SHELL_ENV_MESSAGE=fromtheshell \
   CI=true NODE_PATH=src \
@@ -287,14 +280,7 @@ PORT=3002 \
   REACT_APP_SHELL_ENV_MESSAGE=fromtheshell \
   NODE_PATH=src \
   nohup npm start &>$tmp_server_log &
-while true
-do
-  if grep -q 'You can now view' $tmp_server_log; then
-    break
-  else
-    sleep 1
-  fi
-done
+grep -q 'You can now view' <(tail -f $tmp_server_log)
 E2E_URL="http://localhost:3002" \
   REACT_APP_SHELL_ENV_MESSAGE=fromtheshell \
   CI=true NODE_PATH=src \