change: add post form data in demo

examples/demo.json

@@ -94,6 +94,37 @@
                     "msg": "check args foo2"
                 }
             ]
+        },
+        {
+            "name": "post form data",
+            "request": {
+                "method": "POST",
+                "url": "/post",
+                "params": {
+                    "foo1": "$varFoo1",
+                    "foo2": "${max($a, $b)}"
+                }
+            },
+            "validate": [
+                {
+                    "check": "status_code",
+                    "assert": "equals",
+                    "expect": 200,
+                    "msg": "check status code"
+                },
+                {
+                    "check": "body.form.foo1",
+                    "assert": "length_equals",
+                    "expect": 5,
+                    "msg": "check args foo1"
+                },
+                {
+                    "check": "body.form.foo2",
+                    "assert": "equals",
+                    "expect": "12.3",
+                    "msg": "check args foo2"
+                }
+            ]
         }
     ]
 }