1 files changed, 4 insertions, 3 deletions
diff --git a/tests/async.test b/tests/async.test
index 0f0af0e..2d8f678 100644
--- a/tests/async.test
+++ b/tests/async.test
@@ -19,6 +19,7 @@ if {"::tcltest" ni [namespace children]} {
 ::tcltest::loadTestedCommands
 catch [list package require -exact tcl::test [info patchlevel]]
 
+testConstraint thread [expr {0 == [catch {package require Thread 2.7-}]}]
 testConstraint testasync [llength [info commands testasync]]
 testConstraint knownMsvcBug [expr {![info exists ::env(CI_BUILD_WITH_MSVC)]}]
 
@@ -149,7 +150,7 @@ test async-3.1 {deleting handlers} testasync {
 } {3 del2 {0 0 0 del1 del2}}
 
 test async-4.1 {async interrupting bytecode sequence} -constraints {
-    testasync
+    testasync thread
 } -setup {
     set hm [testasync create async3]
     proc nothing {} {
@@ -178,7 +179,7 @@ test async-4.1 {async interrupting bytecode sequence} -constraints {
     testasync delete $hm
 }
 test async-4.2 {async interrupting straight bytecode sequence} -constraints {
-    testasync
+    testasync thread
 } -setup {
     set hm [testasync create async3]
 } -body {
@@ -203,7 +204,7 @@ test async-4.2 {async interrupting straight bytecode sequence} -constraints {
     testasync delete $hm
 }
 test async-4.3 {async interrupting loop-less bytecode sequence} -constraints {
-    testasync knownMsvcBug
+    testasync thread knownMsvcBug
 } -setup {
     set hm [testasync create async3]
 } -body {