[CI] Add e2e test frame work and doctest (#730)

### What this PR does / why we need it?
Add quickstart doctest CI

### Does this PR introduce _any_ user-facing change?
no

### How was this patch tested?
- CI passed
- Run `/vllm-ascend/tests/e2e/run_doctests.sh`
Related: https://github.com/vllm-project/vllm-ascend/issues/725

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>

tests/e2e/common.sh

@@ -0,0 +1,51 @@
+# bash fonts colors
+cyan='\e[96m'
+yellow='\e[33m'
+red='\e[31m'
+none='\e[0m'
+
+_cyan() { echo -e "${cyan}$*${none}"; }
+_yellow() { echo -e "${yellow}$*${none}"; }
+_red() { echo -e "${red}$*${none}"; }
+
+_info() { _cyan "Info: $*"; }
+_warn() { _yellow "Warn: $*"; }
+_err() { _red "Error: $*" && exit 1; }
+
+CURL_TIMEOUT=1
+CURL_COOLDOWN=5
+CURL_MAX_TRIES=120
+
+function wait_url_ready() {
+  local serve_name="$1"
+  local url="$2"
+  i=0
+  while true; do
+    _info "===> Waiting for ${serve_name} to be ready...${i}s"
+    i=$((i + CURL_COOLDOWN))
+    set +e
+    curl --silent --max-time "$CURL_TIMEOUT" "${url}" >/dev/null
+    result=$?
+    set -e
+    if [ "$result" -eq 0 ]; then
+      break
+    fi
+    if [ "$i" -gt "$CURL_MAX_TRIES" ]; then
+      _info "===> \$CURL_MAX_TRIES exceeded waiting for ${serve_name} to be ready"
+      return 1
+    fi
+    sleep "$CURL_COOLDOWN"
+  done
+  _info "===> ${serve_name} is ready."
+}
+
+function wait_for_exit() {
+  local VLLM_PID="$1"
+  while kill -0 "$VLLM_PID"; do
+    _info "===> Wait for ${VLLM_PID} to exit."
+    sleep 1
+  done
+  _info "===> Wait for ${VLLM_PID} to exit."
+}
+
+SCRIPT_DIR=$(cd "$(dirname "$0")" && pwd)