[Enterprise Search] Allow jest script to run on individual files (ela…

…stic#96589)

x-pack/plugins/enterprise_search/README.md

@@ -38,14 +38,16 @@ yarn test:jest
 yarn test:jest --watch
 ```
 
-Unfortunately coverage collection does not work as automatically, and requires using our handy jest.sh script if you want to run tests on a specific folder and only get coverage numbers for that folder:
+Unfortunately coverage collection does not work as automatically, and requires using our handy jest.sh script if you want to run tests on a specific file or folder and only get coverage numbers for that file or folder:
 
 ```bash
 # Running the jest.sh script from the `x-pack/plugins/enterprise_search` folder (vs. kibana root)
 # will save you time and allow you to Tab to complete folder dir names
 sh jest.sh {YOUR_COMPONENT_DIR}
 sh jest.sh public/applications/shared/kibana
 sh jest.sh server/routes/app_search
+# When testing an individual file, remember to pass the path of the test file, not the source file.
+sh jest.sh public/applications/shared/flash_messages/flash_messages_logic.test.ts
 ```
 
 ### E2E tests

x-pack/plugins/enterprise_search/jest.sh

@@ -1,18 +1,26 @@
 #! /bin/bash
 
 # Whether to run Jest on the entire enterprise_search plugin or a specific component/folder
-FOLDER="${1:-all}"
-if [[ $FOLDER && $FOLDER != "all" ]]
+
+TARGET="${1:-all}"
+if [[ $TARGET && $TARGET != "all" ]]
 then
-  FOLDER=${FOLDER%/} # Strip any trailing slash
-  FOLDER="${FOLDER}/ --collectCoverageFrom='<rootDir>/x-pack/plugins/enterprise_search/${FOLDER}/**/*.{ts,tsx}'"
+  # If this is a file
+  if [[ "$TARGET" == *".ts"* ]]; then
+    PATH_WITHOUT_EXTENSION=${1%%.*}
+    TARGET="${TARGET} --collectCoverageFrom='<rootDir>/x-pack/plugins/enterprise_search/${PATH_WITHOUT_EXTENSION}.{ts,tsx}'"
+  # If this is a folder
+  else
+    TARGET=${TARGET%/} # Strip any trailing slash
+    TARGET="${TARGET}/ --collectCoverageFrom='<rootDir>/x-pack/plugins/enterprise_search/${TARGET}/**/*.{ts,tsx}'"
+  fi
 else
-  FOLDER=''
+  TARGET=''
 fi
 
 # Pass all remaining arguments (e.g., ...rest) from the 2nd arg onwards
 # as an open-ended string. Appends onto to the end the Jest CLI command
 # @see https://jestjs.io/docs/en/cli#options
 ARGS="${*:2}"
 
-yarn test:jest $FOLDER $ARGS
+yarn test:jest $TARGET $ARGS