add unittests

go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/google/uuid v1.3.0
 	github.com/hashicorp/terraform-plugin-docs v0.14.1
 	github.com/hashicorp/terraform-plugin-sdk/v2 v2.17.0
+	github.com/stretchr/testify v1.7.0
 )
 
 require (
@@ -30,6 +31,7 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/sso v1.11.11 // indirect
 	github.com/aws/smithy-go v1.13.5 // indirect
 	github.com/bgentry/speakeasy v0.1.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fatih/color v1.13.0 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/google/go-cmp v0.5.9 // indirect
@@ -63,6 +65,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/oklog/run v1.0.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/posener/complete v1.2.3 // indirect
 	github.com/russross/blackfriday v1.6.0 // indirect
 	github.com/shopspring/decimal v1.3.1 // indirect
@@ -80,4 +83,5 @@ require (
 	google.golang.org/genproto v0.0.0-20200711021454-869866162049 // indirect
 	google.golang.org/grpc v1.46.0 // indirect
 	google.golang.org/protobuf v1.28.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0 // indirect
 )