docs: add more test cases of answer

sample/answer.yaml

@@ -1,6 +1,7 @@
 #!api-testing
 # yaml-language-server: $schema=https://gitee.com/linuxsuren/api-testing/raw/master/sample/api-testing-schema.json
 # see also https://github.com/answerdev/answer
+# start via docker run -d -p 9080:80 -v answer-data:/data --name answer answerdev/answer:1.1.0
 name: Answer
 api: http://localhost:9080/answer/api/v1
 items:
@@ -95,3 +96,67 @@ items:
         {
           "id": "{{.question.data.id}}"
         }
+  - name: search-nagetive-page
+    request:
+      api: /search?q=abc&order=active&page={{randInt -10 0}}&size=20
+      header:
+        Content-Type: application/json
+        Authorization: "{{.login.data.access_token}}"
+    expect:
+      statusCode: 400
+      bodyFieldsExpect:
+        msg: "page must be 1 or greater"
+  - name: search-nagetive-size
+    request:
+      api: /search?q=abc&order=active&page=1&size={{randInt -10 0}}
+      header:
+        Content-Type: application/json
+        Authorization: "{{.login.data.access_token}}"
+    expect:
+      statusCode: 400
+      bodyFieldsExpect:
+        msg: "size must be 1 or greater"
+  - name: search-wrong-order
+    request:
+      api: /search?q=abc&order={{randAlpha 6}}&page=1&size=10
+      header:
+        Content-Type: application/json
+        Authorization: "{{.login.data.access_token}}"
+    expect:
+      statusCode: 400
+      bodyFieldsExpect:
+        msg: "order must be one of [newest active score relevance]"
+  - name: search-not-found
+    request:
+      api: /search?q={{randAlpha 16}}&order={{index (list "newest" "active" "score" "relevance") (randInt 0 3)}}&page=1&size=10
+      header:
+        Content-Type: application/json
+        Authorization: "{{.login.data.access_token}}"
+    expect:
+      bodyFieldsExpect:
+        data/count: 0
+  - name: tags
+    request:
+      api: /tags/page?page=1&page_size=20&query_cond={{index (list "newest" "popular" "name") (randInt 0 2)}}
+      header:
+        Content-Type: application/json
+        Authorization: "{{.login.data.access_token}}"
+    expect:
+      bodyFieldsExpect:
+        data/count: 1
+  - name: tags-invalid-cond
+    request:
+      api: /tags/page?page=1&page_size=20&query_cond={{randAlpha 16}}
+      header:
+        Content-Type: application/json
+        Authorization: "{{.login.data.access_token}}"
+    expect:
+      statusCode: 400
+      bodyFieldsExpect:
+        msg: query_cond must be one of [popular name newest]
+  - name: user-ranking
+    request:
+      api: /user/ranking
+      header:
+        Content-Type: application/json
+        Authorization: "{{.login.data.access_token}}"