diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5c686e063..7948d584a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,19 +14,46 @@ jobs:
       run: bin/package make
     - name: Regression tests
       run: |
-        PS4="$PS4 [ci.yml] "
+        PS4="$PS4[ci.yml] "
         set -o xtrace
         export TZ=UTC
         ulimit -n 1024
         : default regression tests &&
-        script -q -e -c "bin/shtests" &&
+        bin/shtests &&
         : regression tests with OS-provided UTF-8 locales &&
-        LANG=nl_NL.UTF-8 script -q -e -c "bin/shtests --locale --nocompile" &&
-        LANG=ja_JP.UTF-8 script -q -e -c "bin/shtests --locale --nocompile" &&
+        LANG=nl_NL.UTF-8 bin/shtests --locale --nocompile &&
+        LANG=ja_JP.UTF-8 bin/shtests --locale --nocompile &&
         : disable most SHOPTs, rebuild ksh &&
         sed --regexp-extended --in-place=.orig \
           '/^SHOPT (2DMATCH|AUDIT|BGX|BRACEPAT|DYNAMIC|EDPREDICT|ESH|FIXEDARRAY|HISTEXPAND|MULTIBYTE|NAMESPACE|OPTIMIZE|SUID_EXEC|STATS|VSH)=/ s/=1/=0/' \
           src/cmd/ksh93/SHOPT.sh &&
         bin/package make &&
         : default regression tests with SHOPTs disabled &&
-        script -q -e -c "bin/shtests"
+        bin/shtests
+
+  MacOS:
+    name: macOS
+    runs-on: macos-latest
+    steps:
+    - name: Checkout sources
+      uses: actions/checkout@v2
+    - name: Build
+      run: bin/package make
+    - name: Regression tests
+      run: |
+        PS4="$PS4[ci.yml] "
+        set -o xtrace
+        export TZ=UTC
+        ulimit -n 1024
+        : default regression tests &&
+        bin/shtests &&
+        : regression tests with OS-provided UTF-8 locales &&
+        LANG=nl_NL.UTF-8 bin/shtests --locale --nocompile &&
+        LANG=ja_JP.UTF-8 bin/shtests --locale --nocompile &&
+        : disable most SHOPTs, rebuild ksh &&
+        sed -E -i.orig \
+          '/^SHOPT (2DMATCH|AUDIT|BGX|BRACEPAT|DYNAMIC|EDPREDICT|ESH|FIXEDARRAY|HISTEXPAND|MULTIBYTE|NAMESPACE|OPTIMIZE|SUID_EXEC|STATS|VSH)=/ s/=1/=0/' \
+          src/cmd/ksh93/SHOPT.sh &&
+        bin/package make &&
+        : default regression tests with SHOPTs disabled &&
+        bin/shtests
diff --git a/src/cmd/ksh93/tests/basic.sh b/src/cmd/ksh93/tests/basic.sh
index adfcc2371..baabf9821 100755
--- a/src/cmd/ksh93/tests/basic.sh
+++ b/src/cmd/ksh93/tests/basic.sh
@@ -667,21 +667,6 @@ eu=$(
 )
 [[ ${us:1:1} == ${eu:1:1} ]] && err_exit "The time keyword ignores the locale's radix point (both are ${eu:1:1})"
 
-# ======
-# Test for bug in ksh binaries that use posix_spawn() while job control is active.
-# See discussion at: https://github.com/ksh93/ksh/issues/79
-actual=$(
-	"$SHELL" -i <<-\EOF 2>/dev/tty
-	printf '%s\n' 1 2 3 4 5 | while read
-	do	ls /dev/null
-	done 2>&1
-	exit  # suppress extra newline
-	EOF
-)
-expect=$'/dev/null\n/dev/null\n/dev/null\n/dev/null\n/dev/null'
-[[ $actual == "$expect" ]] || err_exit 'Race condition while launching external commands' \
-	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
-
 # ======
 # Expansion of multibyte characters after expansion of single-character names $1..$9, $?, $!, $-, etc.
 function exptest
diff --git a/src/cmd/ksh93/tests/bracket.sh b/src/cmd/ksh93/tests/bracket.sh
index 884337800..52b598a79 100755
--- a/src/cmd/ksh93/tests/bracket.sh
+++ b/src/cmd/ksh93/tests/bracket.sh
@@ -309,10 +309,6 @@ do	if	[[ ! $locales == *$'\n'"${l}"$'\n'* ]] ||
 		done
 	done
 done
-integer n
-if	( : < /dev/tty ) 2>/dev/null && exec {n}< /dev/tty
-then	[[ -t  $n ]] || err_exit "[[ -t  n ]] fails when n > 9"
-fi
 foo=([1]=a [2]=b [3]=c)
 [[ -v foo[1] ]] ||  err_exit 'foo[1] should be set'
 [[ ${foo[1]+x} ]] ||  err_exit '${foo[1]+x} should be x'
@@ -369,37 +365,6 @@ test ! ! x 2> /dev/null || err_exit 'test ! ! x should return 0'
 test ! ! '' 2> /dev/null && err_exit 'test ! ! "" should return non-zero'
 
 # ======
-# Verify that [ -t 1 ] behaves sensibly inside a command substitution.
-
-# This is the simple case that doesn't do any redirection of stdout within the command
-# substitution. Thus the [ -t 1 ] test should be false.
-expect=$'begin\nend'
-actual=$(echo begin; [ -t 1 ] || test -t 1 || [[ -t 1 ]] && echo -t 1 is true; echo end)
-[[ $actual == "$expect" ]] || err_exit 'test -t 1 in comsub fails' \
-	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
-actual=$(echo begin; [ -n X -a -t 1 ] || test -n X -a -t 1 || [[ -n X && -t 1 ]] && echo -t 1 is true; echo end)
-[[ $actual == "$expect" ]] || err_exit 'test -t 1 in comsub fails (compound expression)' \
-	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
-# Same for the ancient compatibility hack for 'test -t' with no arguments.
-actual=$(echo begin; [ -t ] || test -t && echo -t is true; echo end)
-[[ $actual == "$expect" ]] || err_exit 'test -t in comsub fails' \
-	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
-actual=$(echo begin; [ -n X -a -t ] || test -n X -a -t && echo -t is true; echo end)
-[[ $actual == "$expect" ]] || err_exit 'test -t in comsub fails (compound expression)' \
-	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
-
-# This is the more complex case that does redirect stdout within the command substitution to the
-# actual tty. Thus the [ -t 1 ] test should be true.
-actual=$(echo begin; exec >/dev/tty; [ -t 1 ] && test -t 1 && [[ -t 1 ]]) \
-|| err_exit 'test -t 1 in comsub with exec >/dev/tty fails'
-actual=$(echo begin; exec >/dev/tty; [ -n X -a -t 1 ] && test -n X -a -t 1 && [[ -n X && -t 1 ]]) \
-|| err_exit 'test -t 1 in comsub with exec >/dev/tty fails (compound expression)'
-# Same for the ancient compatibility hack for 'test -t' with no arguments.
-actual=$(echo begin; exec >/dev/tty; [ -t ] && test -t) \
-|| err_exit 'test -t in comsub with exec >/dev/tty fails'
-actual=$(echo begin; exec >/dev/tty; [ -n X -a -t ] && test -n X -a -t) \
-|| err_exit 'test -t in comsub with exec >/dev/tty fails (compound expression)'
-
 # The POSIX mode should disable the ancient 'test -t' compatibility hack.
 if	[[ -o ?posix ]]
 then	# need 'eval' in first test, as it's a parser hack, and ksh normally parses ahead of execution
diff --git a/src/cmd/ksh93/tests/pty.sh b/src/cmd/ksh93/tests/pty.sh
index a13223119..02e406802 100755
--- a/src/cmd/ksh93/tests/pty.sh
+++ b/src/cmd/ksh93/tests/pty.sh
@@ -564,5 +564,77 @@ w set -b; sleep .01 &
 u Done
 !
 
+# err_exit #
+# Tests for 'test -t'. These were moved here from bracket.sh because they require a tty.
+cat >test_t.sh <<"EOF"
+integer n
+redirect {n}< /dev/tty
+[[ -t $n ]] && echo OK0 || echo "[[ -t n ]] fails when n > 9"
+# _____ Verify that [ -t 1 ] behaves sensibly inside a command substitution.
+#	This is the simple case that doesn't do any redirection of stdout within
+#	the command substitution. Thus the [ -t 1 ] test should be false.
+expect=$'begin\nend'
+actual=$(echo begin; [ -t 1 ] || test -t 1 || [[ -t 1 ]] && echo -t 1 is true; echo end)
+[[ $actual == "$expect" ]] && echo OK1 || echo 'test -t 1 in comsub fails' \
+	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
+actual=$(echo begin; [ -n X -a -t 1 ] || test -n X -a -t 1 || [[ -n X && -t 1 ]] && echo -t 1 is true; echo end)
+[[ $actual == "$expect" ]] && echo OK2 || echo 'test -t 1 in comsub fails (compound expression)' \
+	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
+# Same for the ancient compatibility hack for 'test -t' with no arguments.
+actual=$(echo begin; [ -t ] || test -t && echo -t is true; echo end)
+[[ $actual == "$expect" ]] && echo OK3 || echo 'test -t in comsub fails' \
+	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
+actual=$(echo begin; [ -n X -a -t ] || test -n X -a -t && echo -t is true; echo end)
+[[ $actual == "$expect" ]] && echo OK4 || echo 'test -t in comsub fails (compound expression)' \
+	"(expected $(printf %q "$expect"), got $(printf %q "$actual"))"
+#	This is the more complex case that does redirect stdout within the command
+#	substitution to the actual tty. Thus the [ -t 1 ] test should be true.
+actual=$(echo begin; exec >/dev/tty; [ -t 1 ] && test -t 1 && [[ -t 1 ]]) \
+&& echo OK5 || echo 'test -t 1 in comsub with exec >/dev/tty fails'
+actual=$(echo begin; exec >/dev/tty; [ -n X -a -t 1 ] && test -n X -a -t 1 && [[ -n X && -t 1 ]]) \
+&& echo OK6 || echo 'test -t 1 in comsub with exec >/dev/tty fails (compound expression)'
+# Same for the ancient compatibility hack for 'test -t' with no arguments.
+actual=$(echo begin; exec >/dev/tty; [ -t ] && test -t) \
+&& echo OK7 || echo 'test -t in comsub with exec >/dev/tty fails'
+actual=$(echo begin; exec >/dev/tty; [ -n X -a -t ] && test -n X -a -t) \
+&& echo OK8 || echo 'test -t in comsub with exec >/dev/tty fails (compound expression)'
+EOF
+tst $LINENO <<"!"
+L test -t 1 inside command substitution
+p :test-1:
+w . ./test_t.sh
+r ^:test-1: \. \./test_t\.sh\r\n$
+r ^\. \./test_t\.sh\r\n$
+r ^OK0\r\n$
+r ^OK1\r\n$
+r ^OK2\r\n$
+r ^OK3\r\n$
+r ^OK4\r\n$
+r ^OK5\r\n$
+r ^OK6\r\n$
+r ^OK7\r\n$
+r ^OK8\r\n$
+r ^:test-2:
+!
+
+# err_exit #
+tst $LINENO <<"!"
+L race condition while launching external commands
+
+# Test for bug in ksh binaries that use posix_spawn() while job control is active.
+# See discussion at: https://github.com/ksh93/ksh/issues/79
+
+p :test-1:
+w printf '%s\\n' 1 2 3 4 5 | while read; do ls /dev/null; done
+r ^:test-1: printf '%s\\n' 1 2 3 4 5 | while read; do ls /dev/null; done\r\n$
+r ^printf '%s\\n' 1 2 3 4 5 | while read; do ls /dev/null; done\r\n$
+r ^/dev/null\r\n$
+r ^/dev/null\r\n$
+r ^/dev/null\r\n$
+r ^/dev/null\r\n$
+r ^/dev/null\r\n$
+r ^:test-2:
+!
+
 # ======
 exit $((Errors<125?Errors:125))
diff --git a/src/cmd/ksh93/tests/shtests b/src/cmd/ksh93/tests/shtests
index 7bbf58dd3..de88b2192 100755
--- a/src/cmd/ksh93/tests/shtests
+++ b/src/cmd/ksh93/tests/shtests
@@ -168,12 +168,6 @@ function valxml
 	return $errors
 }
 
-if	! test -t 1 2>/dev/null 1>/dev/tty
-then	print "The regression tests require a functioning /dev/tty." >&2
-	print "If not available, try script(1) to simulate a tty." >&2
-	exit 128
-fi
-
 command set +o posix 2>/dev/null
 unset DISPLAY FIGNORE HISTFILE POSIXLY_CORRECT _AST_FEATURES
 export ENV=/./dev/null