Add unit tests for Option schemas

schemars/src/json_schema_impls/array.rs

@@ -73,4 +73,17 @@ mod tests {
         assert_eq!(schema.extensions.get("maxItems"), Some(&json!(8)));
         assert_eq!(schema.items, Some(SingleOrVec::from(schema_for::<i32>())));
     }
+
+    // SomeStruct does not implement JsonSchema
+    struct SomeStruct;
+
+    #[test]
+    fn schema_for_empty_array() {
+        let schema = schema_object_for::<[SomeStruct; 0]>();
+        assert_eq!(
+            schema.instance_type,
+            Some(SingleOrVec::from(InstanceType::Array))
+        );
+        assert_eq!(schema.extensions.get("maxItems"), Some(&json!(0)));
+    }
 }

schemars/src/json_schema_impls/core.rs

@@ -47,3 +47,39 @@ impl<T: ?Sized> JsonSchema for std::marker::PhantomData<T> {
         <()>::json_schema(gen)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::gen::*;
+    use crate::tests::{custom_schema_object_for, schema_for, schema_object_for};
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn schema_for_option() {
+        let schema = schema_object_for::<Option<i32>>();
+        assert_eq!(schema.instance_type, None);
+        assert_eq!(schema.extensions.get("nullable"), None);
+        assert_eq!(schema.any_of.is_some(), true);
+        let any_of = schema.any_of.unwrap();
+        assert_eq!(any_of.len(), 2);
+        assert_eq!(any_of[0], schema_for::<i32>());
+        assert_eq!(any_of[1], schema_for::<()>());
+    }
+
+    #[test]
+    fn schema_for_option_with_nullable() {
+        let settings = SchemaSettings {
+            option_nullable: true,
+            option_add_null_type: false,
+            ..Default::default()
+        };
+        let schema = custom_schema_object_for::<Option<i32>>(settings);
+        assert_eq!(
+            schema.instance_type,
+            Some(SingleOrVec::from(InstanceType::Integer))
+        );
+        assert_eq!(schema.extensions.get("nullable"), Some(&json!(true)));
+        assert_eq!(schema.any_of.is_none(), true);
+    }
+}

schemars/src/lib.rs

@@ -28,8 +28,22 @@ pub trait JsonSchema {
 pub mod tests {
     use super::*;
 
+    pub fn schema_object_for<T: JsonSchema>() -> schema::SchemaObject {
+        schema_object(schema_for::<T>())
+    }
+
+    pub fn custom_schema_object_for<T: JsonSchema>(
+        settings: gen::SchemaSettings,
+    ) -> schema::SchemaObject {
+        schema_object(custom_schema_for::<T>(settings))
+    }
+
     pub fn schema_for<T: JsonSchema>() -> schema::Schema {
-        match T::json_schema(&mut gen::SchemaGenerator::default()) {
+        custom_schema_for::<T>(Default::default())
+    }
+
+    pub fn custom_schema_for<T: JsonSchema>(settings: gen::SchemaSettings) -> schema::Schema {
+        match T::json_schema(&mut gen::SchemaGenerator::new(settings)) {
             Ok(s) => s,
             Err(e) => panic!(
                 "Couldn't generate schema object for {}: {}",
@@ -39,10 +53,10 @@ pub mod tests {
         }
     }
 
-    pub fn schema_object_for<T: JsonSchema>() -> schema::SchemaObject {
+    pub fn schema_object(schema: schema::Schema) -> schema::SchemaObject {
-        match schema_for::<T>() {
+        match schema {
             schema::Schema::Object(o) => o,
-            s => panic!("Schema for {} was not an object: {:?}", T::schema_name(), s),
+            s => panic!("Schema was not an object: {:?}", s),
         }
     }
 }