@@ -812,27 +812,21 @@ func TestContainerInvalidLeave(t *testing.T) {

 	}()

 	err = ep.Leave(context.Background(), cnt)

-	if err == nil {

-		t.Fatal("Expected to fail leave from an endpoint which has no active join")

-	}

-	if _, ok := err.(types.ForbiddenError); !ok {

-		t.Fatalf("Failed with unexpected error type: %T. Desc: %s", err, err.Error())

-	}

+	assert.Assert(t, is.ErrorType(err, errdefs.IsForbidden), "Expected to fail leave from an endpoint which has no active join")

+	assert.Check(t, is.Error(err, "cannot leave endpoint with no attached sandbox"))

-	if err = ep.Leave(context.Background(), nil); err == nil {

-		t.Fatalf("Expected to fail leave nil Sandbox")

-	}

-	if _, ok := err.(types.InvalidParameterError); !ok {

-		t.Fatalf("Unexpected error type returned: %T. Desc: %s", err, err.Error())

-	}

+	err = ep.Leave(context.Background(), nil)

+	assert.Assert(t, is.ErrorType(err, errdefs.IsInvalidParameter), "Expected to fail leave with a nil Sandbox")

+	// FIXME(thaJeztah): this error includes the raw data of the sandbox (as `<nil>`), which is not very informative

+	assert.Check(t, is.Error(err, "invalid Sandbox passed to endpoint leave: <nil>"))

 	fsbx := &libnetwork.Sandbox{}

-	if err = ep.Leave(context.Background(), fsbx); err == nil {

-		t.Fatalf("Expected to fail leave with invalid Sandbox")

-	}

-	if _, ok := err.(types.InvalidParameterError); !ok {

-		t.Fatalf("Unexpected error type returned: %T. Desc: %s", err, err.Error())

-	}

+	err = ep.Leave(context.Background(), fsbx)

+	assert.Assert(t, is.ErrorType(err, errdefs.IsInvalidParameter), "Expected to fail leave with invalid Sandbox")

+	//nolint:dupword // Ignore "Duplicate words (map[]) found (dupword)"

+	// FIXME(thaJeztah): this error includes the raw data of the sandbox, which is not very human-readable or informative;

+	//	invalid Sandbox passed to endpoint leave: &{  {{    []} {   [] [] []} map[] false false []} [] <nil> <nil> <nil> {{{} 0} {0 0}} [] map[] map[] <nil> 0 false false false false false []  {0 0} {0 0}}

+	assert.Check(t, is.ErrorContains(err, "invalid Sandbox passed to endpoint leave"))

 }

 func TestEndpointUpdateParent(t *testing.T) {