test UpdateBinary

version_control.go

@@ -203,17 +203,19 @@ func (c *VersionCache) UpdateBinary(ctx context.Context, binary string) (bool, e
 		if err != nil {
 			return needRestart, err
 		}
-		if !same {
-			if err := utils.ForceSymlink(verData.UnpackedPath, verData.SymlinkPath); err != nil {
-				return needRestart, err
-			}
-		}
 
 		if runtime.GOOS == "windows" && verData.UnpackedPath == "" {
 			// This case happens as a result of manual action to fix systems which used the old installer.
 			c.logger.Debug("replacing blank UnpackedPath with DlPath")
 			verData.UnpackedPath = verData.DlPath
 		}
+
+		if !same {
+			if err := utils.ForceSymlink(verData.UnpackedPath, verData.SymlinkPath); err != nil {
+				return needRestart, err
+			}
+		}
+
 		shasum, err := utils.GetFileSum(verData.UnpackedPath)
 		if err == nil && bytes.Equal(shasum, verData.UnpackedSHA) {
 			return false, nil

version_control_test.go

@@ -0,0 +1,96 @@
+package agent
+
+import (
+	"context"
+	"encoding/hex"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/viamrobotics/agent/subsystems/viamserver"
+	"github.com/viamrobotics/agent/utils"
+	"go.viam.com/rdk/logging"
+	"go.viam.com/test"
+)
+
+// replace utils.ViamDirs with t.TempDir for duration of test.
+func mockViamDirs(t *testing.T) {
+	t.Helper()
+	old := utils.ViamDirs
+	t.Cleanup(func() {
+		utils.ViamDirs = old
+	})
+	td := t.TempDir()
+	utils.ViamDirs = map[string]string{
+		"viam": td,
+	}
+	for _, subdir := range []string{"bin", "cache", "tmp", "etc"} {
+		utils.ViamDirs[subdir] = filepath.Join(td, subdir)
+		os.Mkdir(utils.ViamDirs[subdir], 0o755)
+	}
+}
+
+func TestUpdateBinary(t *testing.T) {
+	mockViamDirs(t)
+	logger := logging.NewTestLogger(t)
+
+	vi := VersionInfo{
+		Version:     "0.70.0",
+		SymlinkPath: filepath.Join(utils.ViamDirs["bin"], "viam-server"),
+	}
+	// sha of an empty file
+	var err error
+	vi.UnpackedSHA, err = hex.DecodeString("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
+	test.That(t, err, test.ShouldBeNil)
+
+	vi2 := vi
+	vi2.Version = "0.71.0"
+
+	td := t.TempDir()
+	for _, v := range []*VersionInfo{&vi, &vi2} {
+		f, err := os.Create(filepath.Join(td, "source-binary-"+v.Version))
+		test.That(t, err, test.ShouldBeNil)
+		f.Close()
+		v.URL = "file://" + f.Name()
+	}
+
+	vc := VersionCache{
+		logger: logger,
+		ViamServer: &Versions{
+			TargetVersion: vi.Version,
+			Versions: map[string]*VersionInfo{
+				vi.Version:  &vi,
+				vi2.Version: &vi2,
+			},
+		},
+	}
+
+	// initial install
+	needsRestart, err := vc.UpdateBinary(context.Background(), viamserver.SubsysName)
+	test.That(t, err, test.ShouldBeNil)
+	test.That(t, needsRestart, test.ShouldBeTrue)
+	testExists(t, filepath.Join(utils.ViamDirs["bin"], "viam-server"))
+	testExists(t, filepath.Join(utils.ViamDirs["cache"], "source-binary-"+vi.Version))
+	test.That(t, vi.UnpackedPath, test.ShouldResemble, vi.DlPath)
+
+	// rerun with no change
+	needsRestart, err = vc.UpdateBinary(context.Background(), viamserver.SubsysName)
+	test.That(t, err, test.ShouldBeNil)
+	test.That(t, needsRestart, test.ShouldBeFalse)
+
+	// upgrade
+	vc.ViamServer.TargetVersion = vi2.Version
+	needsRestart, err = vc.UpdateBinary(context.Background(), viamserver.SubsysName)
+	test.That(t, err, test.ShouldBeNil)
+	test.That(t, needsRestart, test.ShouldBeTrue)
+	testExists(t, filepath.Join(utils.ViamDirs["cache"], "source-binary-"+vi2.Version))
+
+	// todo: test custom URL
+}
+
+// assert that a file exists.
+func testExists(t *testing.T, path string) {
+	t.Helper()
+	_, err := os.Stat(path)
+	test.That(t, err, test.ShouldBeNil)
+}