[Dev] Create a script for kick off python test. (#5298)

Co-authored-by: Ubuntu <ubuntu@ip-172-31-28-63.ap-northeast-1.compute.internal>

script/run_pytest.sh

+#!/bin/bash
+
+set -e
+
+usage() {
+cat << EOF
+usage: bash $0 OPTIONS TARGETS
+examples:
+  Run python tests on CPU: bash $0 -c tests/compute/test_subgraph.py
+  Run python tests on GPU: bash $0 -g tests/compute/test_subgraph.py
+
+Run DGL python tests.
+
+OPTIONS:
+  -h           Show this message.
+  -c           Run python tests on CPU.
+  -g           Run python tests on GPU.
+EOF
+}
+
+# Parse flags.
+while getopts "cgh" flag; do
+  if [[ ${flag} == "c" ]]; then
+    device="cpu"
+  elif [[ ${flag} == "g" ]]; then
+    device="gpu"
+  elif [[ ${flag} == "h" ]]; then
+    usage
+    exit 0
+  else
+    usage
+    exit 1
+  fi
+done
+
+if [[ -z ${DGL_HOME} ]]; then
+  echo "ERROR: Please make sure environment variable DGL_HOME is set correctly."
+  exit 1
+fi
+
+if [[ ! ${PWD} == ${DGL_HOME} ]]; then
+  echo "ERROR: This script only works properly from DGL root directory."
+  echo " Current: ${PWD}"
+  echo "DGL_HOME: ${DGL_HOME}"
+  exit 1
+fi
+
+if [[ -z ${device} ]]; then
+  echo "ERROR: Test device unspecified."
+  usage
+  exit 1
+fi
+
+# Reset the index for non-option arguments.
+shift $(($OPTIND-1))
+
+export DGLBACKEND=pytorch
+export DGL_LIBRARY_PATH=${DGL_HOME}/build
+export PYTHONPATH=${DGL_HOME}/python:${DGL_HOME}/tests:$PYTHONPATH
+export DGLTESTDEV=${device}
+export DGL_DOWNLOAD_DIR=${DGL_HOME}/build
+
+if [[ -z $@ ]]; then
+  echo "ERROR: Missing test targets."
+  usage
+  exit 1
+fi
+
+python3 -m pytest -v $@