diff --git a/tests/fixtures/testModel.ts b/tests/fixtures/testModel.ts
index 84a9bb8df..3ccf48682 100644
--- a/tests/fixtures/testModel.ts
+++ b/tests/fixtures/testModel.ts
@@ -1203,7 +1203,7 @@ export class TestClassModel extends TestClassBaseModel {
 }
 
 type NonFunctionPropertyNames<T> = {
-  [K in keyof T]: T[K] extends Function ? never : K;
+  [K in keyof T]: T[K] extends CallableFunction ? never : K;
 }[keyof T];
 type NonFunctionProperties<T> = Pick<T, NonFunctionPropertyNames<T>>;
 export class GetterClass {
diff --git a/tests/unit/swagger/definitionsGeneration/definitions.spec.ts b/tests/unit/swagger/definitionsGeneration/definitions.spec.ts
index da48af4cc..e4e03f092 100644
--- a/tests/unit/swagger/definitionsGeneration/definitions.spec.ts
+++ b/tests/unit/swagger/definitionsGeneration/definitions.spec.ts
@@ -14,10 +14,10 @@ describe('Definition generation', () => {
   const dynamicMetadata = new MetadataGenerator('./fixtures/controllers/getController.ts', undefined, undefined, ['./fixtures/controllers/getController.ts']).Generate();
   const defaultConfig = getDefaultOptions();
   const defaultOptions: ExtendedSpecConfig = { ...defaultConfig.spec, entryFile: defaultConfig.entryFile, noImplicitAdditionalProperties: 'ignore' };
-  const optionsWithNoAdditional = Object.assign<{}, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
+  const optionsWithNoAdditional = Object.assign<object, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
     noImplicitAdditionalProperties: 'silently-remove-extras',
   });
-  const optionsWithXEnumVarnames = Object.assign<{}, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
+  const optionsWithXEnumVarnames = Object.assign<object, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
     xEnumVarnames: true,
   });
   interface SpecAndName {
diff --git a/tests/unit/swagger/parameterDetails3.spec.ts b/tests/unit/swagger/parameterDetails3.spec.ts
index 7ea8e7d89..0e3be3b97 100644
--- a/tests/unit/swagger/parameterDetails3.spec.ts
+++ b/tests/unit/swagger/parameterDetails3.spec.ts
@@ -11,7 +11,7 @@ describe('Parameter generation for OpenAPI 3.0.0', () => {
 
   const defaultConfig = getDefaultOptions();
   const defaultOptions: ExtendedSpecConfig = { ...defaultConfig.spec, noImplicitAdditionalProperties: 'ignore', entryFile: defaultConfig.entryFile };
-  const optionsWithNoAdditional = Object.assign<{}, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
+  const optionsWithNoAdditional = Object.assign<object, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
     noImplicitAdditionalProperties: 'silently-remove-extras',
   });
 
diff --git a/tests/unit/swagger/schemaDetails.spec.ts b/tests/unit/swagger/schemaDetails.spec.ts
index 444966e21..3e9229a35 100644
--- a/tests/unit/swagger/schemaDetails.spec.ts
+++ b/tests/unit/swagger/schemaDetails.spec.ts
@@ -349,7 +349,7 @@ describe('Schema details generation', () => {
 
     describe('methods', () => {
       describe('operationId', () => {
-        const optionsWithOperationIdTemplate = Object.assign<{}, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, getDefaultExtendedOptions(), {
+        const optionsWithOperationIdTemplate = Object.assign<object, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, getDefaultExtendedOptions(), {
           operationIdTemplate: "{{replace controllerName 'Controller' ''}}_{{titleCase method.name}}",
         });
 
diff --git a/tests/unit/swagger/schemaDetails3.spec.ts b/tests/unit/swagger/schemaDetails3.spec.ts
index 77bc45314..f954e6187 100644
--- a/tests/unit/swagger/schemaDetails3.spec.ts
+++ b/tests/unit/swagger/schemaDetails3.spec.ts
@@ -14,13 +14,13 @@ describe('Definition generation for OpenAPI 3.0.0', () => {
   const metadataPost = new MetadataGenerator('./fixtures/controllers/postController.ts').Generate();
 
   const defaultOptions: ExtendedSpecConfig = getDefaultExtendedOptions();
-  const optionsWithNoAdditional = Object.assign<{}, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
+  const optionsWithNoAdditional = Object.assign<object, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
     noImplicitAdditionalProperties: 'silently-remove-extras',
   });
-  const optionsWithXEnumVarnames = Object.assign<{}, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
+  const optionsWithXEnumVarnames = Object.assign<object, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
     xEnumVarnames: true,
   });
-  const optionsWithOperationIdTemplate = Object.assign<{}, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
+  const optionsWithOperationIdTemplate = Object.assign<object, ExtendedSpecConfig, Partial<ExtendedSpecConfig>>({}, defaultOptions, {
     operationIdTemplate: "{{replace controllerName 'Controller' ''}}_{{titleCase method.name}}",
   });
 
@@ -91,7 +91,7 @@ describe('Definition generation for OpenAPI 3.0.0', () => {
     });
 
     it('should have relative URL when no host is defined', () => {
-      const optionsWithNoHost = Object.assign<{}, ExtendedSpecConfig>({}, defaultOptions);
+      const optionsWithNoHost = Object.assign<object, ExtendedSpecConfig>({}, defaultOptions);
       delete optionsWithNoHost.host;
 
       const spec: Swagger.Spec3 = new SpecGenerator3(metadataGet, optionsWithNoHost).GetSpec();