diff --git a/CHANGELOG.md b/CHANGELOG.md
index f4805ac7..4a83a187 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ This changelog documents the changes between release versions.
 
 - Upgrade dependencies to get fix for RUSTSEC-2024-0421, a vulnerability in domain name comparisons ([#138](https://github.com/hasura/ndc-mongodb/pull/138))
 - Aggregations on empty document sets now produce `null` instead of failing with an error ([#136](https://github.com/hasura/ndc-mongodb/pull/136))
+- Handle collection validators with object fields that do not list properties ([#140](https://github.com/hasura/ndc-mongodb/pull/140))
 
 #### Fix for RUSTSEC-2024-0421 / CVE-2024-12224
 
@@ -31,6 +32,25 @@ it uses the affected library exclusively to connect to MongoDB databases, and
 database URLs are supplied by trusted administrators. But better to be safe than
 sorry.
 
+#### Validators with object fields that do not list properties
+
+If a collection validator species an property of type `object`, but does not specify a list of nested properties for that object then we will infer the `ExtendedJSON` type for that property. For a collection created with this set of options would have the type `ExtendedJSON` for its `reactions` field:
+
+```json
+{
+  "validator": {
+    "$jsonSchema": {
+      "bsonType": "object",
+      "properties": {
+        "reactions": { "bsonType": "object" },
+      }
+    }
+  }
+}
+```
+
+If the validator specifies a map of nested properties, but that map is empty, then we interpret that as an empty object type.
+
 ## [1.5.0] - 2024-12-05
 
 ### Added
diff --git a/Cargo.lock b/Cargo.lock
index 10b14f99..0790dd2f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "addr2line"
@@ -1680,14 +1680,13 @@ dependencies = [
 
 [[package]]
 name = "mockall"
-version = "0.12.1"
+version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "43766c2b5203b10de348ffe19f7e54564b64f3d6018ff7648d1e2d6d3a0f0a48"
+checksum = "39a6bfcc6c8c7eed5ee98b9c3e33adc726054389233e201c95dab2d41a3839d2"
 dependencies = [
  "cfg-if",
  "downcast",
  "fragile",
- "lazy_static",
  "mockall_derive",
  "predicates",
  "predicates-tree",
@@ -1695,9 +1694,9 @@ dependencies = [
 
 [[package]]
 name = "mockall_derive"
-version = "0.12.1"
+version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af7cbce79ec385a1d4f54baa90a76401eb15d9cab93685f62e7e9f942aa00ae2"
+checksum = "25ca3004c2efe9011bd4e461bd8256445052b9615405b4f7ea43fc8ca5c20898"
 dependencies = [
  "cfg-if",
  "proc-macro2",
@@ -1799,6 +1798,7 @@ name = "mongodb-cli-plugin"
 version = "1.5.0"
 dependencies = [
  "anyhow",
+ "async-tempfile",
  "clap",
  "configuration",
  "enum-iterator",
diff --git a/crates/cli/Cargo.toml b/crates/cli/Cargo.toml
index 944b2027..1ecc27c3 100644
--- a/crates/cli/Cargo.toml
+++ b/crates/cli/Cargo.toml
@@ -32,6 +32,9 @@ thiserror = "1.0.57"
 tokio = { version = "1.36.0", features = ["full"] }
 
 [dev-dependencies]
+mongodb-agent-common = { path = "../mongodb-agent-common", features = ["test-helpers"] }
+
+async-tempfile = "^0.6.0"
 googletest = "^0.12.0"
 pretty_assertions = "1"
 proptest = "1"
diff --git a/crates/cli/src/introspection/sampling.rs b/crates/cli/src/introspection/sampling.rs
index d557fac1..fcfc5e9d 100644
--- a/crates/cli/src/introspection/sampling.rs
+++ b/crates/cli/src/introspection/sampling.rs
@@ -9,8 +9,11 @@ use configuration::{
 };
 use futures_util::TryStreamExt;
 use mongodb::bson::{doc, Bson, Document};
-use mongodb_agent_common::state::ConnectorState;
-use mongodb_support::BsonScalarType::{self, *};
+use mongodb_agent_common::mongodb::{CollectionTrait as _, DatabaseTrait};
+use mongodb_support::{
+    aggregate::{Pipeline, Stage},
+    BsonScalarType::{self, *},
+};
 
 type ObjectField = WithName<ndc_models::FieldName, schema::ObjectField>;
 type ObjectType = WithName<ndc_models::ObjectTypeName, schema::ObjectType>;
@@ -23,11 +26,10 @@ pub async fn sample_schema_from_db(
     sample_size: u32,
     all_schema_nullable: bool,
     config_file_changed: bool,
-    state: &ConnectorState,
+    db: &impl DatabaseTrait,
     existing_schemas: &HashSet<std::string::String>,
 ) -> anyhow::Result<BTreeMap<std::string::String, Schema>> {
     let mut schemas = BTreeMap::new();
-    let db = state.database();
     let mut collections_cursor = db.list_collections().await?;
 
     while let Some(collection_spec) = collections_cursor.try_next().await? {
@@ -37,7 +39,7 @@ pub async fn sample_schema_from_db(
                 &collection_name,
                 sample_size,
                 all_schema_nullable,
-                state,
+                db,
             )
             .await?;
             if let Some(collection_schema) = collection_schema {
@@ -54,14 +56,17 @@ async fn sample_schema_from_collection(
     collection_name: &str,
     sample_size: u32,
     all_schema_nullable: bool,
-    state: &ConnectorState,
+    db: &impl DatabaseTrait,
 ) -> anyhow::Result<Option<Schema>> {
-    let db = state.database();
     let options = None;
     let mut cursor = db
-        .collection::<Document>(collection_name)
-        .aggregate(vec![doc! {"$sample": { "size": sample_size }}])
-        .with_options(options)
+        .collection(collection_name)
+        .aggregate(
+            Pipeline::new(vec![Stage::Other(doc! {
+                "$sample": { "size": sample_size }
+            })]),
+            options,
+        )
         .await?;
     let mut collected_object_types = vec![];
     let is_collection_type = true;
diff --git a/crates/cli/src/introspection/validation_schema.rs b/crates/cli/src/introspection/validation_schema.rs
index 507355e3..f90b0122 100644
--- a/crates/cli/src/introspection/validation_schema.rs
+++ b/crates/cli/src/introspection/validation_schema.rs
@@ -7,8 +7,8 @@ use configuration::{
 use futures_util::TryStreamExt;
 use mongodb::bson::from_bson;
 use mongodb_agent_common::{
+    mongodb::DatabaseTrait,
     schema::{get_property_description, Property, ValidatorSchema},
-    state::ConnectorState,
 };
 use mongodb_support::BsonScalarType;
 
@@ -19,9 +19,8 @@ type ObjectType = WithName<ndc_models::ObjectTypeName, schema::ObjectType>;
 type ObjectField = WithName<ndc_models::FieldName, schema::ObjectField>;
 
 pub async fn get_metadata_from_validation_schema(
-    state: &ConnectorState,
+    db: &impl DatabaseTrait,
 ) -> Result<BTreeMap<String, Schema>, MongoAgentError> {
-    let db = state.database();
     let mut collections_cursor = db.list_collections().await?;
 
     let mut schemas: Vec<WithName<String, Schema>> = vec![];
@@ -152,10 +151,12 @@ fn make_field_type(object_type_name: &str, prop_schema: &Property) -> (Vec<Objec
 
     match prop_schema {
         Property::Object {
-            bson_type: _,
+            properties: None, ..
+        } => (vec![], Type::ExtendedJSON),
+        Property::Object {
             description: _,
             required,
-            properties,
+            properties: Some(properties),
         } => {
             let type_prefix = format!("{object_type_name}_");
             let (otds, otd_fields): (Vec<Vec<ObjectType>>, Vec<ObjectField>) = properties
@@ -177,7 +178,6 @@ fn make_field_type(object_type_name: &str, prop_schema: &Property) -> (Vec<Objec
             (collected_otds, Type::Object(object_type_name.to_string()))
         }
         Property::Array {
-            bson_type: _,
             description: _,
             items,
         } => {
diff --git a/crates/cli/src/lib.rs b/crates/cli/src/lib.rs
index 3fb92b9d..57bae3d1 100644
--- a/crates/cli/src/lib.rs
+++ b/crates/cli/src/lib.rs
@@ -3,6 +3,8 @@
 mod exit_codes;
 mod introspection;
 mod logging;
+#[cfg(test)]
+mod tests;
 
 #[cfg(feature = "native-query-subcommand")]
 mod native_query;
@@ -13,7 +15,7 @@ use clap::{Parser, Subcommand};
 
 // Exported for use in tests
 pub use introspection::type_from_bson;
-use mongodb_agent_common::state::try_init_state_from_uri;
+use mongodb_agent_common::{mongodb::DatabaseTrait, state::try_init_state_from_uri};
 #[cfg(feature = "native-query-subcommand")]
 pub use native_query::native_query_from_pipeline;
 
@@ -49,7 +51,10 @@ pub struct Context {
 /// Run a command in a given directory.
 pub async fn run(command: Command, context: &Context) -> anyhow::Result<()> {
     match command {
-        Command::Update(args) => update(context, &args).await?,
+        Command::Update(args) => {
+            let connector_state = try_init_state_from_uri(context.connection_uri.as_ref()).await?;
+            update(context, &args, &connector_state.database()).await?
+        }
 
         #[cfg(feature = "native-query-subcommand")]
         Command::NativeQuery(command) => native_query::run(context, command).await?,
@@ -58,12 +63,14 @@ pub async fn run(command: Command, context: &Context) -> anyhow::Result<()> {
 }
 
 /// Update the configuration in the current directory by introspecting the database.
-async fn update(context: &Context, args: &UpdateArgs) -> anyhow::Result<()> {
-    let connector_state = try_init_state_from_uri(context.connection_uri.as_ref()).await?;
-
+async fn update(
+    context: &Context,
+    args: &UpdateArgs,
+    database: &impl DatabaseTrait,
+) -> anyhow::Result<()> {
     let configuration_options =
         configuration::parse_configuration_options_file(&context.path).await?;
-    // Prefer arguments passed to cli, and fallback to the configuration file
+    // Prefer arguments passed to cli, and fall back to the configuration file
     let sample_size = match args.sample_size {
         Some(size) => size,
         None => configuration_options.introspection_options.sample_size,
@@ -88,7 +95,7 @@ async fn update(context: &Context, args: &UpdateArgs) -> anyhow::Result<()> {
 
     if !no_validator_schema {
         let schemas_from_json_validation =
-            introspection::get_metadata_from_validation_schema(&connector_state).await?;
+            introspection::get_metadata_from_validation_schema(database).await?;
         configuration::write_schema_directory(&context.path, schemas_from_json_validation).await?;
     }
 
@@ -97,7 +104,7 @@ async fn update(context: &Context, args: &UpdateArgs) -> anyhow::Result<()> {
         sample_size,
         all_schema_nullable,
         config_file_changed,
-        &connector_state,
+        database,
         &existing_schemas,
     )
     .await?;
diff --git a/crates/cli/src/tests.rs b/crates/cli/src/tests.rs
new file mode 100644
index 00000000..b41ef57e
--- /dev/null
+++ b/crates/cli/src/tests.rs
@@ -0,0 +1,129 @@
+use async_tempfile::TempDir;
+use configuration::read_directory;
+use mongodb::bson::{self, doc, from_document};
+use mongodb_agent_common::mongodb::{test_helpers::mock_stream, MockDatabaseTrait};
+use ndc_models::{CollectionName, FieldName, ObjectField, ObjectType, Type};
+use pretty_assertions::assert_eq;
+
+use crate::{update, Context, UpdateArgs};
+
+#[tokio::test]
+async fn required_field_from_validator_is_non_nullable() -> anyhow::Result<()> {
+    let collection_object_type = collection_schema_from_validator(doc! {
+        "bsonType": "object",
+        "required": ["title"],
+        "properties": {
+            "title": { "bsonType": "string", "maxLength": 100 },
+            "author": { "bsonType": "string", "maxLength": 100 },
+        }
+    })
+    .await?;
+
+    assert_eq!(
+        collection_object_type
+            .fields
+            .get(&FieldName::new("title".into())),
+        Some(&ObjectField {
+            r#type: Type::Named {
+                name: "String".into()
+            },
+            arguments: Default::default(),
+            description: Default::default(),
+        })
+    );
+
+    assert_eq!(
+        collection_object_type
+            .fields
+            .get(&FieldName::new("author".into())),
+        Some(&ObjectField {
+            r#type: Type::Nullable {
+                underlying_type: Box::new(Type::Named {
+                    name: "String".into()
+                })
+            },
+            arguments: Default::default(),
+            description: Default::default(),
+        })
+    );
+
+    Ok(())
+}
+
+#[tokio::test]
+async fn validator_object_with_no_properties_becomes_extended_json_object() -> anyhow::Result<()> {
+    let collection_object_type = collection_schema_from_validator(doc! {
+        "bsonType": "object",
+        "title": "posts validator",
+        "additionalProperties": false,
+        "properties": {
+            "reactions": { "bsonType": "object" },
+        }
+    })
+    .await?;
+
+    assert_eq!(
+        collection_object_type
+            .fields
+            .get(&FieldName::new("reactions".into())),
+        Some(&ObjectField {
+            r#type: Type::Nullable {
+                underlying_type: Box::new(Type::Named {
+                    name: "ExtendedJSON".into()
+                })
+            },
+            arguments: Default::default(),
+            description: Default::default(),
+        })
+    );
+
+    Ok(())
+}
+
+async fn collection_schema_from_validator(validator: bson::Document) -> anyhow::Result<ObjectType> {
+    let mut db = MockDatabaseTrait::new();
+    let config_dir = TempDir::new().await?;
+
+    let context = Context {
+        path: config_dir.to_path_buf(),
+        connection_uri: None,
+        display_color: false,
+    };
+
+    let args = UpdateArgs {
+        sample_size: Some(100),
+        no_validator_schema: None,
+        all_schema_nullable: Some(false),
+    };
+
+    db.expect_list_collections().returning(move || {
+        let collection_spec = doc! {
+            "name": "posts",
+            "type": "collection",
+            "options": {
+                "validator": {
+                    "$jsonSchema": &validator
+                }
+            },
+            "info": { "readOnly": false },
+        };
+        Ok(mock_stream(vec![Ok(
+            from_document(collection_spec).unwrap()
+        )]))
+    });
+
+    update(&context, &args, &db).await?;
+
+    let configuration = read_directory(config_dir).await?;
+
+    let collection = configuration
+        .collections
+        .get(&CollectionName::new("posts".into()))
+        .expect("posts collection");
+    let collection_object_type = configuration
+        .object_types
+        .get(&collection.collection_type)
+        .expect("posts object type");
+
+    Ok(collection_object_type.clone())
+}
diff --git a/crates/mongodb-agent-common/Cargo.toml b/crates/mongodb-agent-common/Cargo.toml
index 6ad0ca18..52511d7e 100644
--- a/crates/mongodb-agent-common/Cargo.toml
+++ b/crates/mongodb-agent-common/Cargo.toml
@@ -4,6 +4,10 @@ description = "logic that is common to v2 and v3 agent versions"
 edition = "2021"
 version.workspace = true
 
+[features]
+default = []
+test-helpers = ["dep:mockall", "dep:pretty_assertions"] # exports mock database impl
+
 [dependencies]
 configuration = { path = "../configuration" }
 mongodb-support = { path = "../mongodb-support" }
@@ -21,9 +25,11 @@ indexmap = { workspace = true }
 indent = "^0.1"
 itertools = { workspace = true }
 lazy_static = "^1.4.0"
+mockall = { version = "^0.13.1", optional = true }
 mongodb = { workspace = true }
 ndc-models = { workspace = true }
 once_cell = "1"
+pretty_assertions = { version = "1", optional = true }
 regex = "1"
 schemars = { version = "^0.8.12", features = ["smol_str"] }
 serde = { workspace = true }
@@ -38,7 +44,7 @@ mongodb-cli-plugin = { path = "../cli" }
 ndc-test-helpers = { path = "../ndc-test-helpers" }
 test-helpers = { path = "../test-helpers" }
 
-mockall = "^0.12.1"
+mockall = "^0.13.1"
 pretty_assertions = "1"
 proptest = "1"
 tokio = { version = "1", features = ["full"] }
diff --git a/crates/mongodb-agent-common/src/mongodb/collection.rs b/crates/mongodb-agent-common/src/mongodb/collection.rs
index ea087442..4e2fca01 100644
--- a/crates/mongodb-agent-common/src/mongodb/collection.rs
+++ b/crates/mongodb-agent-common/src/mongodb/collection.rs
@@ -9,17 +9,17 @@ use mongodb::{
 use mongodb_support::aggregate::Pipeline;
 use serde::de::DeserializeOwned;
 
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 use mockall::automock;
 
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 use super::test_helpers::MockCursor;
 
 /// Abstract MongoDB collection methods. This lets us mock a database connection in tests. The
 /// automock attribute generates a struct called MockCollectionTrait that implements this trait.
 /// The mock provides a variety of methods for mocking and spying on database behavior in tests.
 /// See https://docs.rs/mockall/latest/mockall/
-#[cfg_attr(test, automock(
+#[cfg_attr(any(test, feature = "test-helpers"), automock(
     type DocumentCursor=MockCursor<Document>;
     type RowCursor=MockCursor<T>;
 ))]
@@ -28,8 +28,8 @@ pub trait CollectionTrait<T>
 where
     T: DeserializeOwned + Unpin + Send + Sync + 'static,
 {
-    type DocumentCursor: Stream<Item = Result<Document, Error>> + 'static;
-    type RowCursor: Stream<Item = Result<T, Error>> + 'static;
+    type DocumentCursor: Stream<Item = Result<Document, Error>> + 'static + Unpin;
+    type RowCursor: Stream<Item = Result<T, Error>> + 'static + Unpin;
 
     async fn aggregate<Options>(
         &self,
diff --git a/crates/mongodb-agent-common/src/mongodb/database.rs b/crates/mongodb-agent-common/src/mongodb/database.rs
index 75181b0e..b17a7293 100644
--- a/crates/mongodb-agent-common/src/mongodb/database.rs
+++ b/crates/mongodb-agent-common/src/mongodb/database.rs
@@ -1,17 +1,18 @@
 use async_trait::async_trait;
 use futures_util::Stream;
+use mongodb::results::CollectionSpecification;
 use mongodb::{bson::Document, error::Error, options::AggregateOptions, Database};
 use mongodb_support::aggregate::Pipeline;
 
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 use mockall::automock;
 
 use super::CollectionTrait;
 
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 use super::MockCollectionTrait;
 
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 use super::test_helpers::MockCursor;
 
 /// Abstract MongoDB database methods. This lets us mock a database connection in tests. The
@@ -22,14 +23,16 @@ use super::test_helpers::MockCursor;
 /// I haven't figured out how to make generic associated types work with automock, so  the type
 /// argument for `Collection` values produced via `DatabaseTrait::collection` is fixed to to
 /// `Document`. That's the way we're using collections in this app anyway.
-#[cfg_attr(test, automock(
+#[cfg_attr(any(test, feature = "test-helpers"), automock(
     type Collection = MockCollectionTrait<Document>;
+    type CollectionCursor = MockCursor<CollectionSpecification>;
     type DocumentCursor = MockCursor<Document>;
 ))]
 #[async_trait]
 pub trait DatabaseTrait {
     type Collection: CollectionTrait<Document>;
-    type DocumentCursor: Stream<Item = Result<Document, Error>>;
+    type CollectionCursor: Stream<Item = Result<CollectionSpecification, Error>> + Unpin;
+    type DocumentCursor: Stream<Item = Result<Document, Error>> + Unpin;
 
     async fn aggregate<Options>(
         &self,
@@ -40,11 +43,14 @@ pub trait DatabaseTrait {
         Options: Into<Option<AggregateOptions>> + Send + 'static;
 
     fn collection(&self, name: &str) -> Self::Collection;
+
+    async fn list_collections(&self) -> Result<Self::CollectionCursor, Error>;
 }
 
 #[async_trait]
 impl DatabaseTrait for Database {
     type Collection = mongodb::Collection<Document>;
+    type CollectionCursor = mongodb::Cursor<CollectionSpecification>;
     type DocumentCursor = mongodb::Cursor<Document>;
 
     async fn aggregate<Options>(
@@ -63,4 +69,8 @@ impl DatabaseTrait for Database {
     fn collection(&self, name: &str) -> Self::Collection {
         Database::collection::<Document>(self, name)
     }
+
+    async fn list_collections(&self) -> Result<Self::CollectionCursor, Error> {
+        Database::list_collections(self).await
+    }
 }
diff --git a/crates/mongodb-agent-common/src/mongodb/mod.rs b/crates/mongodb-agent-common/src/mongodb/mod.rs
index 361dbf89..48f16304 100644
--- a/crates/mongodb-agent-common/src/mongodb/mod.rs
+++ b/crates/mongodb-agent-common/src/mongodb/mod.rs
@@ -3,7 +3,7 @@ mod database;
 pub mod sanitize;
 mod selection;
 
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 pub mod test_helpers;
 
 pub use self::{
@@ -11,9 +11,9 @@ pub use self::{
 };
 
 // MockCollectionTrait is generated by automock when the test flag is active.
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 pub use self::collection::MockCollectionTrait;
 
 // MockDatabase is generated by automock when the test flag is active.
-#[cfg(test)]
+#[cfg(any(test, feature = "test-helpers"))]
 pub use self::database::MockDatabaseTrait;
diff --git a/crates/mongodb-agent-common/src/mongodb/test_helpers.rs b/crates/mongodb-agent-common/src/mongodb/test_helpers.rs
index 473db605..c89b3b70 100644
--- a/crates/mongodb-agent-common/src/mongodb/test_helpers.rs
+++ b/crates/mongodb-agent-common/src/mongodb/test_helpers.rs
@@ -14,7 +14,6 @@ use super::{MockCollectionTrait, MockDatabaseTrait};
 // is produced when calling `into_iter` on a `Vec`. - Jesse H.
 //
 // To produce a mock stream use the `mock_stream` function in this module.
-#[cfg(test)]
 pub type MockCursor<T> = futures::stream::Iter<<Vec<Result<T, Error>> as IntoIterator>::IntoIter>;
 
 /// Create a stream that can be returned from mock implementations for
diff --git a/crates/mongodb-agent-common/src/schema.rs b/crates/mongodb-agent-common/src/schema.rs
index 26fd6845..63daf74e 100644
--- a/crates/mongodb-agent-common/src/schema.rs
+++ b/crates/mongodb-agent-common/src/schema.rs
@@ -18,26 +18,22 @@ pub struct ValidatorSchema {
 
 #[derive(Clone, Debug, Deserialize)]
 #[cfg_attr(test, derive(PartialEq))]
-#[serde(untagged)]
+#[serde(tag = "bsonType", rename_all = "camelCase")]
 pub enum Property {
     Object {
-        #[serde(rename = "bsonType", default = "default_bson_type")]
-        #[allow(dead_code)]
-        bson_type: BsonType,
         #[serde(skip_serializing_if = "Option::is_none")]
         description: Option<String>,
         #[serde(skip_serializing_if = "Vec::is_empty", default)]
         required: Vec<String>,
-        properties: IndexMap<String, Property>,
+        #[serde(skip_serializing_if = "Option::is_none")]
+        properties: Option<IndexMap<String, Property>>,
     },
     Array {
-        #[serde(rename = "bsonType", default = "default_bson_type")]
-        #[allow(dead_code)]
-        bson_type: BsonType,
         #[serde(skip_serializing_if = "Option::is_none")]
         description: Option<String>,
         items: Box<Property>,
     },
+    #[serde(untagged)]
     Scalar {
         #[serde(rename = "bsonType", default = "default_bson_scalar_type")]
         bson_type: BsonScalarType,
@@ -49,13 +45,11 @@ pub enum Property {
 pub fn get_property_description(p: &Property) -> Option<String> {
     match p {
         Property::Object {
-            bson_type: _,
             description,
             required: _,
             properties: _,
         } => description.clone(),
         Property::Array {
-            bson_type: _,
             description,
             items: _,
         } => description.clone(),
@@ -78,8 +72,8 @@ fn default_bson_type() -> BsonType {
 mod test {
     use indexmap::IndexMap;
     use mongodb::bson::{bson, from_bson};
-
     use mongodb_support::{BsonScalarType, BsonType};
+    use pretty_assertions::assert_eq;
 
     use super::{Property, ValidatorSchema};
 
@@ -122,10 +116,9 @@ mod test {
         assert_eq!(
             from_bson::<Property>(input)?,
             Property::Object {
-                bson_type: BsonType::Object,
                 description: Some("Name of places".to_owned()),
                 required: vec!["name".to_owned(), "description".to_owned()],
-                properties: IndexMap::from([
+                properties: Some(IndexMap::from([
                     (
                         "name".to_owned(),
                         Property::Scalar {
@@ -142,7 +135,7 @@ mod test {
                             )
                         }
                     )
-                ])
+                ]))
             }
         );
 
@@ -165,13 +158,11 @@ mod test {
         assert_eq!(
             from_bson::<Property>(input)?,
             Property::Array {
-                bson_type: BsonType::Array,
                 description: Some("Location must be an array of objects".to_owned()),
                 items: Box::new(Property::Object {
-                    bson_type: BsonType::Object,
                     description: None,
                     required: vec!["name".to_owned(), "size".to_owned()],
-                    properties: IndexMap::from([
+                    properties: Some(IndexMap::from([
                         (
                             "name".to_owned(),
                             Property::Scalar {
@@ -186,7 +177,7 @@ mod test {
                                 description: None
                             }
                         )
-                    ])
+                    ]))
                 }),
             }
         );
@@ -250,10 +241,9 @@ mod test {
                 properties: IndexMap::from([(
                     "counts".to_owned(),
                     Property::Object {
-                        bson_type: BsonType::Object,
                         description: None,
                         required: vec!["xs".to_owned()],
-                        properties: IndexMap::from([
+                        properties: Some(IndexMap::from([
                             (
                                 "xs".to_owned(),
                                 Property::Scalar {
@@ -268,7 +258,7 @@ mod test {
                                     description: None
                                 }
                             ),
-                        ])
+                        ]))
                     }
                 )])
             }
@@ -300,7 +290,7 @@ mod test {
                     "description": "\"gpa\" must be a double if the field exists"
                 },
                 "address": {
-                    "bsonType": ["object"],
+                    "bsonType": "object",
                     "properties": {
                         "city": { "bsonType": "string" },
                         "street": { "bsonType": "string" }
@@ -350,10 +340,9 @@ mod test {
                     (
                         "address".to_owned(),
                         Property::Object {
-                            bson_type: BsonType::Object,
                             description: None,
                             required: vec![],
-                            properties: IndexMap::from([
+                            properties: Some(IndexMap::from([
                                 (
                                     "city".to_owned(),
                                     Property::Scalar {
@@ -368,7 +357,7 @@ mod test {
                                         description: None,
                                     }
                                 )
-                            ])
+                            ]))
                         }
                     )
                 ]),