From 96ae641c4f611e029acb83254cdcdfb7b8e95348 Mon Sep 17 00:00:00 2001
From: "jsakyle@gmail.com" <jsakyle@gmail.com>
Date: Mon, 1 Mar 2021 21:33:52 -0500
Subject: [PATCH] finalizing implementation and tests

---
 modules/aws/rds_test.go                | 124 +++++++++++++++++++++++++
 test/terraform_aws_rds_example_test.go |   2 +
 2 files changed, 126 insertions(+)
 create mode 100644 modules/aws/rds_test.go

diff --git a/modules/aws/rds_test.go b/modules/aws/rds_test.go
new file mode 100644
index 000000000..642b01621
--- /dev/null
+++ b/modules/aws/rds_test.go
@@ -0,0 +1,124 @@
+package aws
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetRecommendedRdsInstanceType(t *testing.T) {
+	type TestingScenerios struct {
+		name           string
+		region         string
+		databaseEngine string
+		instanceTypes  []string
+		expected       string
+	}
+}
+
+func TestGetRecommendedRdsInstanceTypeHappyPath(t *testing.T) {
+	type TestingScenerios struct {
+		name           string
+		region         string
+		databaseEngine string
+		instanceTypes  []string
+		expected       string
+	}
+
+	testingScenerios := []TestingScenerios{
+		{
+			name:           "US region, mysql, first offering available",
+			region:         "us-east-2",
+			databaseEngine: "mysql",
+			instanceTypes:  []string{"db.t2.micro", "db.t3.micro"},
+			expected:       "db.t2.micro",
+		},
+		{
+			name:           "EU region, postgres, 2nd offering available based on region",
+			region:         "eu-north-1",
+			databaseEngine: "postgres",
+			instanceTypes:  []string{"db.t2.micro", "db.m5.large"},
+			expected:       "db.m5.large",
+		},
+		{
+			name:           "US region, oracle-ee, 2nd offering available based on db type",
+			region:         "us-west-2",
+			databaseEngine: "oracle-ee",
+			instanceTypes:  []string{"db.m5d.xlarge", "db.m5.large"},
+			expected:       "db.m5.large",
+		},
+	}
+
+	for _, scenerio := range testingScenerios {
+		scenerio := scenerio
+
+		t.Run(scenerio.name, func(t *testing.T) {
+			t.Parallel()
+
+			actual, err := GetRecommendedRdsInstanceTypeE(t, scenerio.region, scenerio.databaseEngine, scenerio.instanceTypes)
+			assert.NoError(t, err)
+			assert.Equal(t, scenerio.expected, actual)
+		})
+	}
+}
+
+func TestGetRecommendedRdsInstanceTypeErrors(t *testing.T) {
+	type TestingScenerios struct {
+		name           string
+		region         string
+		databaseEngine string
+		instanceTypes  []string
+	}
+
+	testingScenerios := []TestingScenerios{
+		{
+			name:           "All empty",
+			region:         "",
+			databaseEngine: "",
+			instanceTypes:  nil,
+		},
+		{
+			name:           "No engine or instance type",
+			region:         "us-east-2",
+			databaseEngine: "",
+			instanceTypes:  nil,
+		},
+		{
+			name:           "No instance types",
+			region:         "us-east-2",
+			databaseEngine: "mysql",
+			instanceTypes:  nil,
+		},
+		{
+			name:           "Invalid instance types",
+			region:         "us-east-2",
+			databaseEngine: "mysql",
+			instanceTypes:  []string{"garbage"},
+		},
+		{
+			name:           "Region has no instance type available",
+			region:         "eu-north-1",
+			databaseEngine: "mysql",
+			instanceTypes:  []string{"db.t2.micro"},
+		},
+		{
+			name:           "No instance type available for engine",
+			region:         "us-east-1",
+			databaseEngine: "oracle-ee",
+			instanceTypes:  []string{"db.r5d.large"},
+		},
+	}
+
+	for _, scenerio := range testingScenerios {
+		scenerio := scenerio
+
+		t.Run(scenerio.name, func(t *testing.T) {
+			t.Parallel()
+
+			_, err := GetRecommendedRdsInstanceTypeE(t, scenerio.region, scenerio.databaseEngine, scenerio.instanceTypes)
+			fmt.Println(err)
+			assert.EqualError(t, err, NoRdsInstanceTypeError{InstanceTypeOptions: scenerio.instanceTypes, DatabaseEngine: scenerio.databaseEngine}.Error())
+		})
+	}
+}
diff --git a/test/terraform_aws_rds_example_test.go b/test/terraform_aws_rds_example_test.go
index bd6f1a10a..542c39d3a 100644
--- a/test/terraform_aws_rds_example_test.go
+++ b/test/terraform_aws_rds_example_test.go
@@ -24,6 +24,7 @@ func TestTerraformAwsRdsExample(t *testing.T) {
 	password := "password"
 	// Pick a random AWS region to test in. This helps ensure your code works in all regions.
 	awsRegion := aws.GetRandomStableRegion(t, nil, nil)
+	instanceType := aws.GetRecommendedRdsInstanceType(t, awsRegion, "mysql", []string{"db.t2.micro", "db.t3.micro"})
 
 	// Construct the terraform options with default retryable errors to handle the most common retryable errors in
 	// terraform testing.
@@ -38,6 +39,7 @@ func TestTerraformAwsRdsExample(t *testing.T) {
 			"engine_name":          "mysql",
 			"major_engine_version": "5.7",
 			"family":               "mysql5.7",
+			"instance_class":       instanceType,
 			"username":             username,
 			"password":             password,
 			"allocated_storage":    5,