Add integration tests for update_enging with D-Bus

This commit adds testing docker-compose configuration with D-Bus daemon
running, which we execute unit tests against. This allows mocking
update_engine and testing our interactions with D-Bus.

Closes flatcar#59

Signed-off-by: Mateusz Gozdek <[email protected]>

Author: invidian

.dockerignore

@@ -1 +1,2 @@
 ./bin
+./test/test_bus_socket

Makefile

@@ -51,7 +51,7 @@ clean: ## Cleans build artifacts.
 	rm -rf bin
 
 .PHONY: ci
-ci: check-generate check-vendor check-tidy build test ## Runs checks performed by CI without external dependencies required (e.g. golangci-lint).
+ci: check-generate check-vendor check-tidy build test test-integration ## Runs checks performed by CI without external dependencies required (e.g. golangci-lint).
 
 .PHONY: check-working-tree-clean
 check-working-tree-clean: ## Checks if working directory is clean.
@@ -93,6 +93,20 @@ codespell: ## Runs spell checking.
 	which $(CODESPELL_BIN) >/dev/null 2>&1 || (echo "$(CODESPELL_BIN) binary not found, skipping spell checking"; exit 0)
 	$(CODESPELL_BIN) --skip $(CODESPELL_SKIP) --ignore-words .codespell.ignorewords --check-filenames --check-hidden
 
+.PHONY: test-up
+test-up: ## Starts testing D-Bus instance in Docker container using docker-compose.
+	env UID=$$(id -u) docker-compose -f test/docker-compose.yml up -d
+
+.PHONY: test-down
+test-down: ## Tears down testing D-Bus instance created by 'test-up'.
+	docker-compose -f test/docker-compose.yml down
+
+.PHONY: test-integration
+test-integration: test-up
+test-integration: ## Runs integration tests using D-Bus running in Docker container.
+	FLUO_TEST_DBUS_SOCKET=$$(realpath ./test/test_bus_socket) go test -mod=vendor -count 1 ./...
+	make test-down
+
 .PHONY: help
 help: ## Prints help message.
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'

pkg/updateengine/client_test.go

@@ -0,0 +1,131 @@
+package updateengine_test
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	dbus "github.com/godbus/dbus/v5"
+
+	"github.com/kinvolk/flatcar-linux-update-operator/pkg/updateengine"
+)
+
+//nolint:paralleltest // Test uses environment variables, which are global.
+func Test_Connecting_to_non_existing_system_bus_fails(t *testing.T) {
+	if err := os.Setenv("DBUS_SYSTEM_BUS_ADDRESS", "foo"); err != nil {
+		t.Fatalf("Setting systemd bus address: %v", err)
+	}
+
+	if _, err := updateengine.New(); err == nil {
+		t.Fatalf("Creating client should fail when unable to connect to system bus")
+	}
+}
+
+//nolint:funlen,tparallel // Test uses environment variables, which are global.
+func Test_Emitted_status_parses(t *testing.T) {
+	var (
+		lastCheckedTime  int64   = 10
+		progress         float64 = 20
+		currentOperation         = updateengine.UpdateStatusVerifying
+		newVersion               = "1.2.3"
+		newSize          int64   = 30
+	)
+
+	withMockGetStatus(t, func(message dbus.Message) (int64, float64, string, string, int64, *dbus.Error) {
+		return lastCheckedTime, progress, currentOperation, newVersion, newSize, nil
+	})
+
+	c, err := updateengine.New()
+	if err != nil {
+		t.Fatalf("Creating client should succeed, got: %v", err)
+	}
+
+	stop := make(chan struct{})
+	ch := make(chan updateengine.Status, 1)
+
+	go c.ReceiveStatuses(ch, stop)
+
+	status := <-ch
+
+	t.Run("first_value_as_last_checked_time", func(t *testing.T) {
+		t.Parallel()
+
+		if status.LastCheckedTime != lastCheckedTime {
+			t.Errorf("Expected %v, got %v", lastCheckedTime, status.LastCheckedTime)
+		}
+	})
+
+	t.Run("second_value_as_progress", func(t *testing.T) {
+		t.Parallel()
+
+		if status.Progress != progress {
+			t.Errorf("Expected %v, got %v", progress, status.Progress)
+		}
+	})
+
+	t.Run("third_value_as_current_operation", func(t *testing.T) {
+		t.Parallel()
+
+		if status.CurrentOperation != currentOperation {
+			t.Errorf("Expected %q, got %q", currentOperation, status.CurrentOperation)
+		}
+	})
+
+	t.Run("forth_value_as_new_version", func(t *testing.T) {
+		t.Parallel()
+
+		if status.NewVersion != newVersion {
+			t.Errorf("Expected %q, got %q", newVersion, status.NewVersion)
+		}
+	})
+
+	t.Run("fifth_value_as_new_size", func(t *testing.T) {
+		t.Parallel()
+
+		if status.NewSize != newSize {
+			t.Errorf("Expected %v, got %v", newSize, status.NewSize)
+		}
+	})
+}
+
+const (
+	testDbusSocketEnv = "FLUO_TEST_DBUS_SOCKET"
+)
+
+func testSystemConnection(t *testing.T) *dbus.Conn {
+	t.Helper()
+
+	socket := os.Getenv(testDbusSocketEnv)
+	if socket == "" {
+		t.Skipf("%q environment variable empty", testDbusSocketEnv)
+	}
+
+	if err := os.Setenv("DBUS_SYSTEM_BUS_ADDRESS", fmt.Sprintf("unix:path=%s", socket)); err != nil {
+		t.Fatalf("Setting systemd bus address: %v", err)
+	}
+
+	conn, err := dbus.SystemBus()
+	if err != nil {
+		t.Fatalf("Opening private connection to system bus: %v", err)
+	}
+
+	return conn
+}
+
+func withMockGetStatus(t *testing.T, fn interface{}) {
+	t.Helper()
+
+	conn := testSystemConnection(t)
+
+	if _, err := conn.RequestName("com.coreos.update1", 0); err != nil {
+		t.Fatalf("Requesting name: %v", err)
+	}
+
+	tbl := map[string]interface{}{
+		"GetStatus": fn,
+	}
+
+	if err := conn.ExportMethodTable(tbl, "/com/coreos/update1", "com.coreos.update1.Manager"); err != nil {
+		t.Fatalf("Exporting method table: %v", err)
+	}
+}

test/Dockerfile

@@ -0,0 +1,3 @@
+FROM alpine:3.13
+
+RUN apk add -U dbus

test/docker-compose.yml

@@ -0,0 +1,13 @@
+version: "3.8"
+services:
+  dbus:
+    build: .
+    command:
+      - dbus-daemon
+      - --nofork
+      - --config-file=/var/run/dbus/testing.conf
+      - --nosyslog
+    user: "${UID}"
+    volumes:
+      - ./:/var/run/dbus
+      - /etc/passwd:/etc/passwd

test/testing.conf

@@ -0,0 +1,10 @@
+<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig>
+  <listen>unix:path=/var/run/dbus/test_bus_socket</listen>
+  <policy context="default">
+    <allow send_destination="*"/>
+    <allow receive_sender="*"/>
+    <allow own="*"/>
+  </policy>
+</busconfig>