diff --git a/blob_test.go b/blob_test.go
index 5d086ba..e50236c 100644
--- a/blob_test.go
+++ b/blob_test.go
@@ -24,6 +24,7 @@ import (
 )
 
 func TestBlobGet(t *testing.T) {
+	t.Parallel()
 	blobRepo := "/proj/repo"
 	privateRepo := "/proj/private"
 	ctx := context.Background()
@@ -299,6 +300,7 @@ func TestBlobGet(t *testing.T) {
 }
 
 func TestBlobPut(t *testing.T) {
+	t.Parallel()
 	blobRepo := "/proj/repo"
 	// privateRepo := "/proj/private"
 	ctx := context.Background()
@@ -736,6 +738,7 @@ func TestBlobPut(t *testing.T) {
 }
 
 func TestBlobCopy(t *testing.T) {
+	t.Parallel()
 	blobRepoA := "/proj/repo-a"
 	blobRepoB := "/proj/repo-b"
 	ctx := context.Background()
diff --git a/cmd/regbot/root.go b/cmd/regbot/root.go
index 4caae61..3f5ddd6 100644
--- a/cmd/regbot/root.go
+++ b/cmd/regbot/root.go
@@ -33,7 +33,7 @@ type rootCmd struct {
 	format    string // for Go template formatting of various commands
 }
 
-// TODO: remove these globals
+// TODO: remove globals, configure tests with t.Parallel
 var (
 	conf      *Config
 	log       *logrus.Logger
diff --git a/cmd/regctl/root.go b/cmd/regctl/root.go
index 70a26ef..9ce5684 100644
--- a/cmd/regctl/root.go
+++ b/cmd/regctl/root.go
@@ -22,6 +22,7 @@ More details at https://github.com/regclient/regclient`
 	UserAgent = "regclient/regctl"
 )
 
+// TODO: remove global, configure tests with t.Parallel
 var (
 	log *logrus.Logger
 )
diff --git a/cmd/regsync/root.go b/cmd/regsync/root.go
index 4746a85..faf8e0b 100644
--- a/cmd/regsync/root.go
+++ b/cmd/regsync/root.go
@@ -55,7 +55,7 @@ type rootCmd struct {
 	missing   bool
 }
 
-// TODO: remove globals
+// TODO: remove globals, configure tests with t.Parallel
 var (
 	conf      *Config
 	log       *logrus.Logger
diff --git a/config/credhelper_test.go b/config/credhelper_test.go
index 5a9516b..1319c01 100644
--- a/config/credhelper_test.go
+++ b/config/credhelper_test.go
@@ -7,6 +7,7 @@ import (
 )
 
 func TestCredHelper(t *testing.T) {
+	// cannot run cred helper in parallel because of OS working directory race conditions
 	tests := []struct {
 		name        string
 		host        string
diff --git a/config/docker_test.go b/config/docker_test.go
index 7d33cc1..13dc89c 100644
--- a/config/docker_test.go
+++ b/config/docker_test.go
@@ -9,6 +9,7 @@ import (
 )
 
 func TestDocker(t *testing.T) {
+	// cannot run cred helper in parallel because of OS working directory race conditions
 	curPath := os.Getenv("PATH")
 	pwd, err := os.Getwd()
 	if err != nil {
@@ -122,6 +123,7 @@ func TestDocker(t *testing.T) {
 }
 
 func TestLoadMissing(t *testing.T) {
+	// cannot run cred helper in parallel because of OS working directory race conditions
 	cf := conffile.New(conffile.WithFullname("testdata/missing.json"))
 	h, err := dockerParse(cf)
 	if err != nil {
diff --git a/config/host_test.go b/config/host_test.go
index d684f45..685b046 100644
--- a/config/host_test.go
+++ b/config/host_test.go
@@ -12,6 +12,7 @@ import (
 )
 
 func TestConfig(t *testing.T) {
+	// cannot run cred helper in parallel because of OS working directory race conditions
 	cwd, err := os.Getwd()
 	if err != nil {
 		t.Errorf("failed checking current directory: %v", err)
@@ -439,5 +440,4 @@ func TestConfig(t *testing.T) {
 			}
 		})
 	}
-
 }
diff --git a/image_test.go b/image_test.go
index 6189ab5..36cd1f6 100644
--- a/image_test.go
+++ b/image_test.go
@@ -14,6 +14,7 @@ import (
 )
 
 func TestImageCheckBase(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	fsOS := rwfs.OSNew("")
 	fsMem := rwfs.MemNew()
@@ -62,7 +63,7 @@ func TestImageCheckBase(t *testing.T) {
 		return
 	}
 
-	tests := []struct {
+	tt := []struct {
 		name      string
 		opts      []ImageOpts
 		r         ref.Ref
@@ -112,14 +113,14 @@ func TestImageCheckBase(t *testing.T) {
 		},
 	}
 
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			err := rc.ImageCheckBase(ctx, tt.r, tt.opts...)
-			if tt.expectErr != nil {
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			err := rc.ImageCheckBase(ctx, tc.r, tc.opts...)
+			if tc.expectErr != nil {
 				if err == nil {
 					t.Errorf("check base did not fail")
-				} else if err.Error() != tt.expectErr.Error() && !errors.Is(err, tt.expectErr) {
-					t.Errorf("error mismatch, expected %v, received %v", tt.expectErr, err)
+				} else if err.Error() != tc.expectErr.Error() && !errors.Is(err, tc.expectErr) {
+					t.Errorf("error mismatch, expected %v, received %v", tc.expectErr, err)
 				}
 			} else {
 				if err != nil {
@@ -131,6 +132,7 @@ func TestImageCheckBase(t *testing.T) {
 }
 
 func TestCopy(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	// create regclient
 	delayInit, _ := time.ParseDuration("0.05s")
@@ -212,6 +214,7 @@ func TestCopy(t *testing.T) {
 }
 
 func TestExportImport(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	// copy testdata images into memory
 	fsOS := rwfs.OSNew("")
diff --git a/internal/ascii/ascii_test.go b/internal/ascii/ascii_test.go
index cb13566..1ad5e11 100644
--- a/internal/ascii/ascii_test.go
+++ b/internal/ascii/ascii_test.go
@@ -6,6 +6,7 @@ import (
 )
 
 func TestIsWriterTerminal(t *testing.T) {
+	t.Parallel()
 	b := make([]byte, 10)
 	buf := bytes.NewBuffer(b)
 	if IsWriterTerminal(buf) {
diff --git a/internal/ascii/lines_test.go b/internal/ascii/lines_test.go
index e2a90a5..67a55cf 100644
--- a/internal/ascii/lines_test.go
+++ b/internal/ascii/lines_test.go
@@ -7,6 +7,7 @@ import (
 )
 
 func TestLinesWidthZero(t *testing.T) {
+	t.Parallel()
 	b := make([]byte, 0, 1024)
 	buf := bytes.NewBuffer(b)
 	l := NewLines(buf)
@@ -70,6 +71,7 @@ func TestLinesWidthZero(t *testing.T) {
 }
 
 func TestLinesWidthSet(t *testing.T) {
+	t.Parallel()
 	b := make([]byte, 0, 1024)
 	buf := bytes.NewBuffer(b)
 	l := NewLines(buf)
diff --git a/internal/ascii/progress_test.go b/internal/ascii/progress_test.go
index b608c1b..10912fb 100644
--- a/internal/ascii/progress_test.go
+++ b/internal/ascii/progress_test.go
@@ -6,6 +6,7 @@ import (
 )
 
 func TestProgress(t *testing.T) {
+	t.Parallel()
 	// TODO: test scenarios and compare output
 	b := make([]byte, 0, 1024)
 	buf := bytes.NewBuffer(b)
diff --git a/internal/auth/auth_test.go b/internal/auth/auth_test.go
index d253e1d..f9903a0 100644
--- a/internal/auth/auth_test.go
+++ b/internal/auth/auth_test.go
@@ -15,6 +15,7 @@ import (
 )
 
 func TestParseAuthHeader(t *testing.T) {
+	t.Parallel()
 	var tests = []struct {
 		name, in string
 		wantC    []Challenge
@@ -91,6 +92,7 @@ func TestParseAuthHeader(t *testing.T) {
 
 // TestAuth checks the auth interface using a mock http server
 func TestAuth(t *testing.T) {
+	t.Parallel()
 	clientID := "testClient"
 	token1Resp, _ := json.Marshal(BearerToken{
 		Token:     "token1",
@@ -308,6 +310,7 @@ func TestAuth(t *testing.T) {
 }
 
 func TestBearer(t *testing.T) {
+	t.Parallel()
 	useragent := "regclient/test"
 	user := "user"
 	pass := "testpass"
diff --git a/internal/cache/cache_test.go b/internal/cache/cache_test.go
index 266d354..34716da 100644
--- a/internal/cache/cache_test.go
+++ b/internal/cache/cache_test.go
@@ -9,6 +9,7 @@ import (
 )
 
 func TestCache(t *testing.T) {
+	t.Parallel()
 	testData := []string{
 		"a", "b", "c", "d", "e", "f", "g", "h", "i", "j",
 		"k", "l", "m", "n", "o", "p", "q", "r", "s", "t",
diff --git a/internal/conffile/conffile_test.go b/internal/conffile/conffile_test.go
index 81fc3f2..906e51c 100644
--- a/internal/conffile/conffile_test.go
+++ b/internal/conffile/conffile_test.go
@@ -12,6 +12,7 @@ import (
 
 // test New
 func TestNew(t *testing.T) {
+	t.Parallel()
 	testEnvFileVar, testEnvFileVal := "TEST_CONFFILE_NEW", "./test-filename.json"
 	os.Setenv(testEnvFileVar, testEnvFileVal)
 	testEnvDirVar, testEnvDirVal := "TEST_CONFDIR_NEW", "./test-dirname"
@@ -100,6 +101,7 @@ func TestNew(t *testing.T) {
 
 // TestWriteOpen test Write and Open using MemFS
 func TestWriteOpen(t *testing.T) {
+	t.Parallel()
 	memfs := rwfs.MemNew()
 	confContent := []byte("hello test")
 	cf := New(WithFS(memfs), WithFullname("test.json"))
diff --git a/internal/diff/diff_test.go b/internal/diff/diff_test.go
index 08ac284..d015907 100644
--- a/internal/diff/diff_test.go
+++ b/internal/diff/diff_test.go
@@ -3,6 +3,7 @@ package diff
 import "testing"
 
 func TestDiff(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name         string
 		a, b, expect []string
diff --git a/internal/httplink/httplink_test.go b/internal/httplink/httplink_test.go
index d1cf23f..7025ee0 100644
--- a/internal/httplink/httplink_test.go
+++ b/internal/httplink/httplink_test.go
@@ -8,6 +8,7 @@ import (
 )
 
 func TestParseErr(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name    string
 		headers []string
@@ -60,6 +61,7 @@ func TestParseErr(t *testing.T) {
 }
 
 func TestParseGet(t *testing.T) {
+	t.Parallel()
 	headerComplex := []string{`</path1>; rel="next", </path2> ; rel="next", / ; rel=index `, `</print>; media=print`, `/link, /reader; media=reader; type=x`}
 	tests := []struct {
 		name          string
@@ -135,5 +137,4 @@ func TestParseGet(t *testing.T) {
 			}
 		})
 	}
-
 }
diff --git a/internal/limitread/limitread_test.go b/internal/limitread/limitread_test.go
index 980b807..45611ab 100644
--- a/internal/limitread/limitread_test.go
+++ b/internal/limitread/limitread_test.go
@@ -10,6 +10,7 @@ import (
 )
 
 func TestLimitRead(t *testing.T) {
+	t.Parallel()
 	byte0 := []byte("")
 	byte5 := []byte("12345")
 	byte10 := []byte("1234567890")
diff --git a/internal/muset/muset_test.go b/internal/muset/muset_test.go
index 6442110..b682ce7 100644
--- a/internal/muset/muset_test.go
+++ b/internal/muset/muset_test.go
@@ -7,6 +7,7 @@ import (
 )
 
 func TestMuset(t *testing.T) {
+	t.Parallel()
 	// test acquiring sets of locks, sleep between changes to force out race conditions
 	var muA, muB, muC sync.Mutex
 	// empty set
diff --git a/internal/reghttp/http_test.go b/internal/reghttp/http_test.go
index 2d293ee..9edbabc 100644
--- a/internal/reghttp/http_test.go
+++ b/internal/reghttp/http_test.go
@@ -27,6 +27,7 @@ import (
 // TODO: test rate limits and concurrency
 
 func TestRegHttp(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	// setup req/resp
 	useragent := "regclient/test"
diff --git a/internal/rwfs/mem_test.go b/internal/rwfs/mem_test.go
index 866fb3e..6f18111 100644
--- a/internal/rwfs/mem_test.go
+++ b/internal/rwfs/mem_test.go
@@ -3,6 +3,7 @@ package rwfs
 import "testing"
 
 func TestMem(t *testing.T) {
+	t.Parallel()
 	fs := MemNew()
 	if fs == nil {
 		t.Errorf("MemNew returned nil")
diff --git a/internal/rwfs/os_test.go b/internal/rwfs/os_test.go
index d16df7f..ccf20a5 100644
--- a/internal/rwfs/os_test.go
+++ b/internal/rwfs/os_test.go
@@ -5,6 +5,7 @@ import (
 )
 
 func TestOS(t *testing.T) {
+	t.Parallel()
 	tempDir := t.TempDir()
 	t.Logf("tempdir: %s", tempDir)
 	fs := OSNew(tempDir)
diff --git a/internal/throttle/throttle_test.go b/internal/throttle/throttle_test.go
index ab41d49..8574026 100644
--- a/internal/throttle/throttle_test.go
+++ b/internal/throttle/throttle_test.go
@@ -9,6 +9,7 @@ import (
 )
 
 func TestNil(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	var tNil *Throttle
 	err := tNil.Acquire(ctx)
@@ -30,6 +31,7 @@ func TestNil(t *testing.T) {
 }
 
 func TestSingleThrottle(t *testing.T) {
+	t.Parallel()
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	wg := sync.WaitGroup{}
@@ -125,6 +127,7 @@ func TestSingleThrottle(t *testing.T) {
 }
 
 func TestCapacity(t *testing.T) {
+	t.Parallel()
 	t3 := New(3)
 	wg := sync.WaitGroup{}
 	ctx := context.Background()
@@ -194,6 +197,7 @@ func TestCapacity(t *testing.T) {
 }
 
 func TestMulti(t *testing.T) {
+	t.Parallel()
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	tList := make([]*Throttle, 4)
diff --git a/internal/timejson/timejson_test.go b/internal/timejson/timejson_test.go
index 62fa2c6..60ce6d1 100644
--- a/internal/timejson/timejson_test.go
+++ b/internal/timejson/timejson_test.go
@@ -9,6 +9,7 @@ import (
 )
 
 func TestMarshal(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name   string
 		d      Duration
@@ -41,6 +42,7 @@ func TestMarshal(t *testing.T) {
 }
 
 func TestUnmarshal(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name   string
 		str    string
diff --git a/internal/units/size_test.go b/internal/units/size_test.go
index dc3efdd..4ae478a 100644
--- a/internal/units/size_test.go
+++ b/internal/units/size_test.go
@@ -3,6 +3,7 @@ package units
 import "testing"
 
 func TestHuman(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name   string
 		size   float64
diff --git a/internal/version/version_test.go b/internal/version/version_test.go
index 3e5e0c4..31ae7a8 100644
--- a/internal/version/version_test.go
+++ b/internal/version/version_test.go
@@ -6,6 +6,7 @@ import (
 )
 
 func TestVersion(t *testing.T) {
+	t.Parallel()
 	i := GetInfo()
 	ij, err := json.MarshalIndent(i, "", "  ")
 	if err != nil {
diff --git a/manifest_test.go b/manifest_test.go
index 0c6806f..331b1e3 100644
--- a/manifest_test.go
+++ b/manifest_test.go
@@ -25,6 +25,7 @@ import (
 )
 
 func TestManifest(t *testing.T) {
+	t.Parallel()
 	repoPath := "/proj"
 	getTag := "get"
 	headTag := "head"
@@ -378,5 +379,4 @@ func TestManifest(t *testing.T) {
 			return
 		}
 	})
-
 }
diff --git a/mod/mod_test.go b/mod/mod_test.go
index 7aa4229..88d1f10 100644
--- a/mod/mod_test.go
+++ b/mod/mod_test.go
@@ -19,6 +19,7 @@ import (
 )
 
 func TestMod(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	// copy testdata images into memory
 	fsOS := rwfs.OSNew("")
@@ -745,6 +746,7 @@ func TestMod(t *testing.T) {
 }
 
 func TestInList(t *testing.T) {
+	t.Parallel()
 	t.Run("match", func(t *testing.T) {
 		if !inListStr(types.MediaTypeDocker2LayerGzip, mtWLTar) {
 			t.Errorf("did not find docker layer in tar whitelist")
diff --git a/mod/time_test.go b/mod/time_test.go
index 5a57472..5c1f9e2 100644
--- a/mod/time_test.go
+++ b/mod/time_test.go
@@ -8,6 +8,7 @@ import (
 )
 
 func TestTimeNow(t *testing.T) {
+	t.Parallel()
 	curEnv, envIsSet := os.LookupEnv(epocEnv)
 	defer func() {
 		if envIsSet {
diff --git a/regclient_test.go b/regclient_test.go
index 5f72dfe..2bef173 100644
--- a/regclient_test.go
+++ b/regclient_test.go
@@ -9,6 +9,7 @@ import (
 )
 
 func TestNew(t *testing.T) {
+	t.Parallel()
 	logPtr := logrus.New()
 	tt := []struct {
 		name   string
@@ -99,5 +100,4 @@ func TestNew(t *testing.T) {
 			}
 		})
 	}
-
 }
diff --git a/scheme/ocidir/blob_test.go b/scheme/ocidir/blob_test.go
index 8417f2a..8c08248 100644
--- a/scheme/ocidir/blob_test.go
+++ b/scheme/ocidir/blob_test.go
@@ -15,6 +15,7 @@ import (
 )
 
 func TestBlob(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	f := rwfs.OSNew("")
 	o := New(WithFS(f))
@@ -168,5 +169,4 @@ func TestBlob(t *testing.T) {
 	if !bytes.Equal(fBytes, bBytes) {
 		t.Errorf("blob put bytes, expected %s, saw %s", string(bBytes), string(fBytes))
 	}
-
 }
diff --git a/scheme/ocidir/close_test.go b/scheme/ocidir/close_test.go
index a6ffbca..e234f55 100644
--- a/scheme/ocidir/close_test.go
+++ b/scheme/ocidir/close_test.go
@@ -12,6 +12,7 @@ import (
 )
 
 func TestClose(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	fsOS := rwfs.OSNew("")
 	fsMem := rwfs.MemNew()
@@ -84,5 +85,4 @@ func TestClose(t *testing.T) {
 			fh.Close()
 		}
 	}
-
 }
diff --git a/scheme/ocidir/manifest_test.go b/scheme/ocidir/manifest_test.go
index f83d9c7..5610a81 100644
--- a/scheme/ocidir/manifest_test.go
+++ b/scheme/ocidir/manifest_test.go
@@ -19,6 +19,7 @@ import (
 )
 
 func TestManifest(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	// copy testdata images into memory
 	fsOS := rwfs.OSNew("")
@@ -226,5 +227,4 @@ func TestManifest(t *testing.T) {
 	if err != nil {
 		t.Errorf("could not query manifest after pushing dup tag")
 	}
-
 }
diff --git a/scheme/ocidir/ocidir_test.go b/scheme/ocidir/ocidir_test.go
index 856c094..3585658 100644
--- a/scheme/ocidir/ocidir_test.go
+++ b/scheme/ocidir/ocidir_test.go
@@ -34,6 +34,7 @@ func cmpSliceString(a, b []string) bool {
 }
 
 func TestIndex(t *testing.T) {
+	t.Parallel()
 	// ctx := context.Background()
 	fsMem := rwfs.MemNew()
 	o := New(WithFS(fsMem))
diff --git a/scheme/ocidir/referrer_test.go b/scheme/ocidir/referrer_test.go
index 6418931..f7f7ce5 100644
--- a/scheme/ocidir/referrer_test.go
+++ b/scheme/ocidir/referrer_test.go
@@ -19,6 +19,7 @@ import (
 )
 
 func TestReferrer(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	fsOS := rwfs.OSNew("")
 	fsMem := rwfs.MemNew()
@@ -348,7 +349,6 @@ func TestReferrer(t *testing.T) {
 			return
 		}
 	})
-
 }
 
 func mapStringStringEq(a, b map[string]string) bool {
diff --git a/scheme/ocidir/tag_test.go b/scheme/ocidir/tag_test.go
index f728e2b..da27eae 100644
--- a/scheme/ocidir/tag_test.go
+++ b/scheme/ocidir/tag_test.go
@@ -11,6 +11,7 @@ import (
 )
 
 func TestTag(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	fsOS := rwfs.OSNew("")
 	fsMem := rwfs.MemNew()
diff --git a/scheme/reg/blob_test.go b/scheme/reg/blob_test.go
index 7a8143c..80e62f1 100644
--- a/scheme/reg/blob_test.go
+++ b/scheme/reg/blob_test.go
@@ -25,6 +25,7 @@ import (
 )
 
 func TestBlobGet(t *testing.T) {
+	t.Parallel()
 	blobRepo := "/proj/repo"
 	externalRepo := "/proj/external"
 	privateRepo := "/proj/private"
@@ -359,10 +360,10 @@ func TestBlobGet(t *testing.T) {
 			t.Errorf("Error does not match \"ErrUnauthorized\": %v", err)
 		}
 	})
-
 }
 
 func TestBlobPut(t *testing.T) {
+	t.Parallel()
 	blobRepo := "/proj/repo"
 	// privateRepo := "/proj/private"
 	ctx := context.Background()
diff --git a/scheme/reg/manifest_test.go b/scheme/reg/manifest_test.go
index bdcb741..39c9f97 100644
--- a/scheme/reg/manifest_test.go
+++ b/scheme/reg/manifest_test.go
@@ -25,6 +25,7 @@ import (
 )
 
 func TestManifest(t *testing.T) {
+	t.Parallel()
 	repoPath := "/proj"
 	getTag := "get"
 	bigTag := "big"
diff --git a/scheme/reg/referrer_test.go b/scheme/reg/referrer_test.go
index 37d94b8..595582e 100644
--- a/scheme/reg/referrer_test.go
+++ b/scheme/reg/referrer_test.go
@@ -26,6 +26,7 @@ import (
 )
 
 func TestReferrer(t *testing.T) {
+	t.Parallel()
 	// setup http server with and without API support
 	ctx := context.Background()
 	repoPath := "/proj"
diff --git a/scheme/reg/repo_test.go b/scheme/reg/repo_test.go
index 563dc7a..a195e1b 100644
--- a/scheme/reg/repo_test.go
+++ b/scheme/reg/repo_test.go
@@ -21,6 +21,7 @@ import (
 )
 
 func TestRepo(t *testing.T) {
+	t.Parallel()
 	ctx := context.Background()
 	partialLen := 2
 	listRegistry := []string{
diff --git a/scheme/reg/tag_test.go b/scheme/reg/tag_test.go
index 504f1d5..0d7c329 100644
--- a/scheme/reg/tag_test.go
+++ b/scheme/reg/tag_test.go
@@ -25,6 +25,7 @@ import (
 )
 
 func TestTag(t *testing.T) {
+	t.Parallel()
 	repoPath := "/proj"
 	repoPath2 := "/proj2"
 	pageLen := 2
diff --git a/types/descriptor_test.go b/types/descriptor_test.go
index 5c52fa1..4e0789d 100644
--- a/types/descriptor_test.go
+++ b/types/descriptor_test.go
@@ -13,6 +13,7 @@ import (
 )
 
 func TestDescriptorData(t *testing.T) {
+	t.Parallel()
 	tt := []struct {
 		name     string
 		d        Descriptor
@@ -80,6 +81,7 @@ func TestDescriptorData(t *testing.T) {
 }
 
 func TestDescriptorEq(t *testing.T) {
+	t.Parallel()
 	digA := digest.FromString("test A")
 	digB := digest.FromString("test B")
 	tt := []struct {
@@ -447,6 +449,7 @@ func TestDescriptorEq(t *testing.T) {
 }
 
 func TestDataJSON(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name     string
 		dJSON    []byte
@@ -534,6 +537,7 @@ func TestDataJSON(t *testing.T) {
 }
 
 func TestDescriptorSearch(t *testing.T) {
+	t.Parallel()
 	dAMD64 := Descriptor{
 		MediaType: MediaTypeOCI1Manifest,
 		Size:      12345,
@@ -781,5 +785,4 @@ func TestDescriptorSearch(t *testing.T) {
 			}
 		})
 	}
-
 }
diff --git a/types/manifest/manifest_test.go b/types/manifest/manifest_test.go
index 7147664..52542aa 100644
--- a/types/manifest/manifest_test.go
+++ b/types/manifest/manifest_test.go
@@ -401,6 +401,7 @@ var (
 )
 
 func TestNew(t *testing.T) {
+	t.Parallel()
 	r, _ := ref.New("localhost:5000/test:latest")
 	var manifestDockerSchema2, manifestInvalid schema2.Manifest
 	var manifestDockerSchema1Signed schema1.SignedManifest
@@ -1059,6 +1060,7 @@ func TestNew(t *testing.T) {
 }
 
 func TestModify(t *testing.T) {
+	t.Parallel()
 	addDigest := digest.FromString("new layer digest")
 	addDesc := types.Descriptor{
 		Digest: addDigest,
@@ -1288,6 +1290,7 @@ func TestModify(t *testing.T) {
 
 // test set methods for config, layers, and manifest list
 func TestSet(t *testing.T) {
+	t.Parallel()
 	addDigest := digest.FromString("new digest")
 	addDesc := types.Descriptor{
 		Digest: addDigest,
@@ -1478,7 +1481,6 @@ func TestSet(t *testing.T) {
 			} else if tt.expectAnnot {
 				t.Errorf("annotation methods not found")
 			}
-
 		})
 	}
 }
diff --git a/types/mediatype_test.go b/types/mediatype_test.go
index 6a023fa..b2fb7c2 100644
--- a/types/mediatype_test.go
+++ b/types/mediatype_test.go
@@ -3,6 +3,7 @@ package types
 import "testing"
 
 func TestMediaTypeBase(t *testing.T) {
+	t.Parallel()
 	tt := []struct {
 		name   string
 		orig   string
@@ -28,5 +29,4 @@ func TestMediaTypeBase(t *testing.T) {
 			}
 		})
 	}
-
 }
diff --git a/types/ref/ref_test.go b/types/ref/ref_test.go
index c573a0c..1fbe641 100644
--- a/types/ref/ref_test.go
+++ b/types/ref/ref_test.go
@@ -9,6 +9,7 @@ import (
 )
 
 func TestRef(t *testing.T) {
+	t.Parallel()
 	var tests = []struct {
 		name       string
 		ref        string
@@ -422,6 +423,7 @@ func TestRef(t *testing.T) {
 }
 
 func TestCommon(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name string
 		str  string
@@ -459,6 +461,7 @@ func TestCommon(t *testing.T) {
 }
 
 func TestEqual(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name       string
 		a, b       Ref
@@ -596,6 +599,7 @@ func TestEqual(t *testing.T) {
 }
 
 func TestToReg(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name   string
 		inRef  string
@@ -635,5 +639,4 @@ func TestToReg(t *testing.T) {
 			}
 		})
 	}
-
 }
diff --git a/types/referrer/referrer_test.go b/types/referrer/referrer_test.go
index 48a1178..316d416 100644
--- a/types/referrer/referrer_test.go
+++ b/types/referrer/referrer_test.go
@@ -169,6 +169,7 @@ func init() {
 }
 
 func TestEmpty(t *testing.T) {
+	t.Parallel()
 	// create an empty list and full list, test is empty
 	rlEmpty := &ReferrerList{
 		Descriptors: []types.Descriptor{},
@@ -215,6 +216,7 @@ func TestEmpty(t *testing.T) {
 }
 
 func TestAdd(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name        string
 		m           manifest.Manifest
@@ -284,6 +286,7 @@ func TestAdd(t *testing.T) {
 }
 
 func TestDelete(t *testing.T) {
+	t.Parallel()
 	rl := &ReferrerList{
 		Descriptors: []types.Descriptor{
 			dOCIImg,
diff --git a/types/repo/repolist_test.go b/types/repo/repolist_test.go
index 9e5dd72..abfba90 100644
--- a/types/repo/repolist_test.go
+++ b/types/repo/repolist_test.go
@@ -12,6 +12,7 @@ import (
 )
 
 func TestNew(t *testing.T) {
+	t.Parallel()
 	emptyRaw := []byte("{}")
 	registryList := []string{"library/alpine", "library/debian", "library/golang"}
 	registryRaw := []byte(fmt.Sprintf(`{"repositories":["%s"]}`, strings.Join(registryList, `","`)))
diff --git a/types/tag/taglist_test.go b/types/tag/taglist_test.go
index bd0c18a..c5bfa19 100644
--- a/types/tag/taglist_test.go
+++ b/types/tag/taglist_test.go
@@ -15,6 +15,7 @@ import (
 )
 
 func TestNew(t *testing.T) {
+	t.Parallel()
 	emptyRaw := []byte("{}")
 	registryTags := []string{"cache", "edge", "edge-alpine", "alpine", "latest"}
 	reqURL, err := url.Parse("http://localhost:5000/v2/regclient/test/tag/list")
@@ -245,6 +246,7 @@ func TestNew(t *testing.T) {
 }
 
 func TestAppend(t *testing.T) {
+	t.Parallel()
 	expectTags := []string{"1", "2", "3", "4", "5", "6"}
 	tl1, err := New(
 		WithTags(expectTags[:3]),
diff --git a/types/warning/warning_test.go b/types/warning/warning_test.go
index d61a0a2..916061d 100644
--- a/types/warning/warning_test.go
+++ b/types/warning/warning_test.go
@@ -10,6 +10,7 @@ import (
 )
 
 func TestWarning(t *testing.T) {
+	t.Parallel()
 	msg1 := "test 1"
 	msg2 := "test 2"
 	ctxBase := context.Background()