Attribute for defining examples (#23)

schemars/tests/examples.rs

@@ -0,0 +1,25 @@
+mod util;
+use schemars::JsonSchema;
+use serde::Serialize;
+use util::*;
+
+#[derive(Default, Debug, JsonSchema, Serialize)]
+#[schemars(example = "Struct::default", example = "null")]
+pub struct Struct {
+    #[schemars(example = "eight", example = "null")]
+    foo: i32,
+    bar: bool,
+    #[schemars(example = "null")]
+    baz: Option<&'static str>,
+}
+
+fn eight() -> i32 {
+    8
+}
+
+fn null() -> () {}
+
+#[test]
+fn examples() -> TestResult {
+    test_default_generated_schema::<Struct>("examples")
+}

schemars/tests/expected/examples.json

@@ -0,0 +1,39 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Struct",
+  "examples": [
+    {
+      "bar": false,
+      "baz": null,
+      "foo": 0
+    },
+    null
+  ],
+  "type": "object",
+  "required": [
+    "bar",
+    "foo"
+  ],
+  "properties": {
+    "bar": {
+      "type": "boolean"
+    },
+    "baz": {
+      "examples": [
+        null
+      ],
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "foo": {
+      "examples": [
+        8,
+        null
+      ],
+      "type": "integer",
+      "format": "int32"
+    }
+  }
+}