Use Err prefix for always return error implementation (#12874)

Make this package consistent with a way more used package
https://github.com/open-telemetry/opentelemetry-collector/blob/main/consumer/consumertest/err.go#L15

Signed-off-by: Bogdan Drutu <[email protected]>

Author: bogdandrutu

.chloggen/use-err.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: deprecation
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: extensionauthtest
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Deprecate NewErrorClient in favor of NewErrClient.
+
+# One or more tracking issues or pull requests related to the change
+issues: [12874]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

config/confighttp/confighttp_test.go

@@ -455,7 +455,7 @@ func TestHTTPClientSettingWithAuthConfig(t *testing.T) {
 			shouldErr: true,
 			host: &mockHost{
 				ext: map[component.ID]component.Component{
-					mockID: extensionauthtest.NewErrorClient(errors.New("error")),
+					mockID: extensionauthtest.NewErr(errors.New("error")),
 				},
 			},
 		},

extension/extensionauth/extensionauthtest/error_client.go renamed to extension/extensionauth/extensionauthtest/err.go

@@ -4,6 +4,7 @@
 package extensionauthtest // import "go.opentelemetry.io/collector/extension/extensionauth/extensionauthtest"
 
 import (
+	"context"
 	"net/http"
 
 	"google.golang.org/grpc/credentials"
@@ -14,26 +15,32 @@ import (
 )
 
 var (
-	_ extension.Extension      = (*errorClient)(nil)
-	_ extensionauth.HTTPClient = (*errorClient)(nil)
-	_ extensionauth.GRPCClient = (*errorClient)(nil)
+	_ extension.Extension      = (*errClient)(nil)
+	_ extensionauth.HTTPClient = (*errClient)(nil)
+	_ extensionauth.GRPCClient = (*errClient)(nil)
 )
 
-type errorClient struct {
+type errClient struct {
 	component.StartFunc
 	component.ShutdownFunc
 	extensionauth.ClientPerRPCCredentialsFunc
 	extensionauth.ClientRoundTripperFunc
+	extensionauth.ServerAuthenticateFunc
 }
 
-// NewErrorClient returns a new [extension.Extension] that implements the [extensionauth.HTTPClient] and [extensionauth.GRPCClient] and always returns an error on both methods.
-func NewErrorClient(err error) extension.Extension {
-	return &errorClient{
+// Deprecated: [v0.125.0] Use NewErr.
+var NewErrorClient = NewErr
+
+// NewErr returns a new [extension.Extension] that implements all
+// extensionauth interface and always returns an error.
+func NewErr(err error) extension.Extension {
+	return &errClient{
 		ClientRoundTripperFunc: func(http.RoundTripper) (http.RoundTripper, error) {
 			return nil, err
 		},
 		ClientPerRPCCredentialsFunc: func() (credentials.PerRPCCredentials, error) {
 			return nil, err
 		},
+		ServerAuthenticateFunc: func(ctx context.Context, _ map[string][]string) (context.Context, error) { return ctx, err },
 	}
 }

extension/extensionauth/extensionauthtest/error_client_test.go renamed to extension/extensionauth/extensionauthtest/err_test.go

@@ -4,6 +4,7 @@
 package extensionauthtest
 
 import (
+	"context"
 	"errors"
 	"testing"
 
@@ -13,7 +14,7 @@ import (
 )
 
 func TestErrorClient(t *testing.T) {
-	client := NewErrorClient(errors.New("error"))
+	client := NewErr(errors.New("error"))
 
 	httpClient, ok := client.(extensionauth.HTTPClient)
 	require.True(t, ok)
@@ -24,4 +25,9 @@ func TestErrorClient(t *testing.T) {
 	require.True(t, ok)
 	_, err = grpcClient.PerRPCCredentials()
 	require.Error(t, err)
+
+	server, ok := client.(extensionauth.Server)
+	require.True(t, ok)
+	_, err = server.Authenticate(context.Background(), map[string][]string{})
+	require.Error(t, err)
 }