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Health Checks v3.9.3 ​

Version history: Embedded SDK introduced in v3.7.0. Current API since v3.16.0; the legacy sdk.Run / mock.Stub / mock.Verify API was removed in v3.20.0. See the Upgrade Guide.

GripMock supports stubbing the standard gRPC health service:

  • grpc.health.v1.Health/Check — unary health status
  • grpc.health.v1.Health/Watch — streaming health status (useful for testing health transitions)

Use it to test how a client reacts to a dependency changing health state, for example NOT_SERVING -> SERVING.

Protected service: gripmock ​

The service key gripmock is reserved for GripMock internal readiness.

  • An internal stub is created automatically at server startup with NOT_SERVING status
  • When the server becomes ready, the status updates to SERVING
  • User stubs targeting service: "gripmock" are stored but always overridden by the internal stub
go
srv := sdk.NewServer(t, sdk.WithProtoFiles("examples/projects/greeter/service.proto"))
defer srv.Close()

// This stub is stored but always overridden by internal stub:
srv.ExpectUnary("/grpc.health.v1.Health/Check").
    Match("service", "gripmock").
    Return("status", "NOT_SERVING")

client := grpc_health_v1.NewHealthClient(srv.Conn())
resp, err := client.Check(t.Context(), &grpc_health_v1.HealthCheckRequest{
    Service: "gripmock",
})
// Returns SERVING (internal stub)
require.NoError(t, err)
require.Equal(t, grpc_health_v1.HealthCheckResponse_SERVING, resp.GetStatus())

Mocking Check ​

go
func TestHealthCheckMockedViaSDK(t *testing.T) {
    srv := sdk.NewServer(t, sdk.WithProtoFiles("examples/projects/greeter/service.proto"))
    defer srv.Close()

    srv.ExpectUnary("/grpc.health.v1.Health/Check").
        Match("service", "examples.health.backend").
        Return("status", "NOT_SERVING")

    client := grpc_health_v1.NewHealthClient(srv.Conn())
    resp, err := client.Check(t.Context(), &grpc_health_v1.HealthCheckRequest{
        Service: "examples.health.backend",
    })
    require.NoError(t, err)
    require.Equal(t, grpc_health_v1.HealthCheckResponse_NOT_SERVING, resp.GetStatus())
}

gripmock service behavior ​

Requests for the gripmock service return the internal stub status:

go
func TestHealthCheckGripmockProtectedViaSDK(t *testing.T) {
    srv := sdk.NewServer(t, sdk.WithProtoFiles("examples/projects/greeter/service.proto"))
    defer srv.Close()

    // Even with a stub that targets "gripmock"...
    srv.ExpectUnary("/grpc.health.v1.Health/Check").
        Match("service", "gripmock").
        Return("status", "NOT_SERVING")

    client := grpc_health_v1.NewHealthClient(srv.Conn())
    resp, err := client.Check(t.Context(), &grpc_health_v1.HealthCheckRequest{
        Service: "gripmock",
    })
    require.NoError(t, err)
    // Internal stub overrides user stub — SERVING
    require.Equal(t, grpc_health_v1.HealthCheckResponse_SERVING, resp.GetStatus())
}

Unknown service fallback ​

If no stub matches and the service is not gripmock, the request returns NotFound:

go
func TestHealthCheckUnknownServiceFallbackViaSDK(t *testing.T) {
    srv := sdk.NewServer(t, sdk.WithProtoFiles("examples/projects/greeter/service.proto"))
    defer srv.Close()

    client := grpc_health_v1.NewHealthClient(srv.Conn())
    resp, err := client.Check(t.Context(), &grpc_health_v1.HealthCheckRequest{
        Service: "examples.health.unknown",
    })
    require.Error(t, err)
    require.Equal(t, codes.NotFound, status.Code(err))
}

Mocking Watch stream ​

The Watch method returns a stream of health status updates. You can stub it to return a sequence of statuses:

go
func TestRunHealthWatchMockedStreamViaSDK(t *testing.T) {
    srv := sdk.NewServer(t, sdk.WithProtoFiles("examples/projects/greeter/service.proto"))
    defer srv.Close()

    srv.ExpectServerStream("/grpc.health.v1.Health/Watch").
        Match("service", "examples.health.watch").
        SendStream(
            map[string]any{"status": "NOT_SERVING"},
            map[string]any{"status": "SERVING"},
        )

    client := grpc_health_v1.NewHealthClient(srv.Conn())
    ctx, cancel := context.WithCancel(t.Context())
    defer cancel()

    stream, err := client.Watch(ctx, &grpc_health_v1.HealthCheckRequest{
        Service: "examples.health.watch",
    })
    require.NoError(t, err)

    first, err := stream.Recv()
    require.NoError(t, err)
    require.Equal(t, grpc_health_v1.HealthCheckResponse_NOT_SERVING, first.GetStatus())

    second, err := stream.Recv()
    require.NoError(t, err)
    require.Equal(t, grpc_health_v1.HealthCheckResponse_SERVING, second.GetStatus())
}

Watch with delay ​

You can add a delay before individual stream messages using Delay:

go
srv.ExpectServerStream("/grpc.health.v1.Health/Watch").
    Match("service", "examples.health.watch").
    SendStream(
        sdk.Delay(10*time.Millisecond, "status", "NOT_SERVING"),
        map[string]any{"status": "SERVING"},
    )

Full runnable example ​

See:

  • examples/projects/health/stubs.yaml
  • examples/projects/health/case_check_mocked_not_serving.gctf
  • examples/projects/health/case_watch_mocked_stream.gctf
  • examples/projects/health/case_check_gripmock_protected.gctf