[feature] Allow admins to send test emails (#1620)

* [feature] Allow admins to send test emails

* implement unwrap on new error type

* add + use gtserror types

* GoToSocial Email Test -> GoToSocial Test Email

* add + use getInstance db call

* removed unused "unknown" error type

3 files changed, 30 insertions, 0 deletions

diff --git a/internal/db/bundb/instance.go b/internal/db/bundb/instance.go
index c40551212..b4bdeb1d9 100644
--- a/internal/db/bundb/instance.go
+++ b/internal/db/bundb/instance.go
@@ -97,6 +97,20 @@ func (i *instanceDB) CountInstanceDomains(ctx context.Context, domain string) (i
 	return count, nil
 }
 
+func (i *instanceDB) GetInstance(ctx context.Context, domain string) (*gtsmodel.Instance, db.Error) {
+	instance := &gtsmodel.Instance{}
+
+	if err := i.conn.
+		NewSelect().
+		Model(instance).
+		Where("? = ?", bun.Ident("instance.domain"), domain).
+		Scan(ctx); err != nil {
+		return nil, i.conn.ProcessError(err)
+	}
+
+	return instance, nil
+}
+
 func (i *instanceDB) GetInstancePeers(ctx context.Context, includeSuspended bool) ([]*gtsmodel.Instance, db.Error) {
 	instances := []*gtsmodel.Instance{}
 
diff --git a/internal/db/bundb/instance_test.go b/internal/db/bundb/instance_test.go
index 3edb68370..4269df5ca 100644
--- a/internal/db/bundb/instance_test.go
+++ b/internal/db/bundb/instance_test.go
@@ -23,6 +23,7 @@ import (
 
 	"github.com/stretchr/testify/suite"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
 )
 
 type InstanceTestSuite struct {
@@ -59,6 +60,18 @@ func (suite *InstanceTestSuite) TestCountInstanceDomains() {
 	suite.Equal(2, count)
 }
 
+func (suite *InstanceTestSuite) TestGetInstanceOK() {
+	instance, err := suite.db.GetInstance(context.Background(), "localhost:8080")
+	suite.NoError(err)
+	suite.NotNil(instance)
+}
+
+func (suite *InstanceTestSuite) TestGetInstanceNonexistent() {
+	instance, err := suite.db.GetInstance(context.Background(), "doesnt.exist.com")
+	suite.ErrorIs(err, db.ErrNoEntries)
+	suite.Nil(instance)
+}
+
 func (suite *InstanceTestSuite) TestGetInstancePeers() {
 	peers, err := suite.db.GetInstancePeers(context.Background(), false)
 	suite.NoError(err)
diff --git a/internal/db/instance.go b/internal/db/instance.go
index 85d094d96..dff471193 100644
--- a/internal/db/instance.go
+++ b/internal/db/instance.go
@@ -34,6 +34,9 @@ type Instance interface {
 	// CountInstanceDomains returns the number of known instances known that the given domain federates with.
 	CountInstanceDomains(ctx context.Context, domain string) (int, Error)
 
+	// GetInstance returns the instance entry for the given domain, if it exists.
+	GetInstance(ctx context.Context, domain string) (*gtsmodel.Instance, Error)
+
 	// GetInstanceAccounts returns a slice of accounts from the given instance, arranged by ID.
 	GetInstanceAccounts(ctx context.Context, domain string, maxID string, limit int) ([]*gtsmodel.Account, Error)