diff --git a/test/asm/multiple-else.err b/test/asm/multiple-else.err
index 76d7b41a..dd987043 100644
--- a/test/asm/multiple-else.err
+++ b/test/asm/multiple-else.err
@@ -1,2 +1,2 @@
-FATAL: multiple-else.asm(11):
-    Found ELSE after an ELSE block
+FATAL: multiple-else.asm(11):
+    Found ELSE after an ELSE block
diff --git a/test/asm/narg-decreases-after-shift.err b/test/asm/narg-decreases-after-shift.err
index a6eb6fd5..cb16698f 100644
--- a/test/asm/narg-decreases-after-shift.err
+++ b/test/asm/narg-decreases-after-shift.err
@@ -1,2 +1,2 @@
-warning: narg-decreases-after-shift.asm(14) -> narg-decreases-after-shift.asm::testing(9): [-Wmacro-shift]
-    Cannot shift macro arguments past their end
+warning: narg-decreases-after-shift.asm(14) -> narg-decreases-after-shift.asm::testing(9): [-Wmacro-shift]
+    Cannot shift macro arguments past their end
diff --git a/test/asm/strrpl.err b/test/asm/strrpl.err
index a1196175..43e4ccf8 100644
--- a/test/asm/strrpl.err
+++ b/test/asm/strrpl.err
@@ -1,2 +1,2 @@
-warning: strrpl.asm(4): [-Wempty-strrpl]
-    STRRPL: Cannot replace an empty string
+warning: strrpl.asm(4): [-Wempty-strrpl]
+    STRRPL: Cannot replace an empty string
diff --git a/test/asm/symbol-invalid-macro-arg.out b/test/asm/symbol-invalid-macro-arg.out
index 7af2c10a..c4b1afa8 100644
--- a/test/asm/symbol-invalid-macro-arg.out
+++ b/test/asm/symbol-invalid-macro-arg.out
@@ -1 +1 @@
-$A
+$A
diff --git a/test/asm/test.sh b/test/asm/test.sh
index 33edcd20..17353bf5 100755
--- a/test/asm/test.sh
+++ b/test/asm/test.sh
@@ -30,7 +30,7 @@ RGBASM=../../rgbasm
 RGBLINK=../../rgblink
 
 tryDiff () {
-	if ! diff -u --strip-trailing-cr "$1" "$2"; then
+	if ! diff -au --strip-trailing-cr "$1" "$2"; then
 		echo "${bold}${red}${i%.asm}${variant}.$3 mismatch!${rescolors}${resbold}"
 		false
 	fi
diff --git a/test/fix/color.err b/test/fix/color.err
index 59c96e73..fc253168 100644
--- a/test/fix/color.err
+++ b/test/fix/color.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the CGB flag
+warning: Overwrote a non-zero byte in the CGB flag
diff --git a/test/fix/compatible.err b/test/fix/compatible.err
index 59c96e73..fc253168 100644
--- a/test/fix/compatible.err
+++ b/test/fix/compatible.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the CGB flag
+warning: Overwrote a non-zero byte in the CGB flag
diff --git a/test/fix/custom-logo.err b/test/fix/custom-logo.err
index 8fb4635a..345a97be 100644
--- a/test/fix/custom-logo.err
+++ b/test/fix/custom-logo.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the logo
+warning: Overwrote a non-zero byte in the logo
diff --git a/test/fix/gameid.err b/test/fix/gameid.err
index 4e420e16..3129bb73 100644
--- a/test/fix/gameid.err
+++ b/test/fix/gameid.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the manufacturer code
+warning: Overwrote a non-zero byte in the manufacturer code
diff --git a/test/fix/header-edit.err b/test/fix/header-edit.err
index 76e06c7c..c7137fc0 100644
--- a/test/fix/header-edit.err
+++ b/test/fix/header-edit.err
@@ -1,2 +1,2 @@
-warning: Overwrote a non-zero byte in the CGB flag
-warning: Overwrote a non-zero byte in the header checksum
+warning: Overwrote a non-zero byte in the CGB flag
+warning: Overwrote a non-zero byte in the header checksum
diff --git a/test/fix/header-trash.err b/test/fix/header-trash.err
index 5fa313aa..021584b6 100644
--- a/test/fix/header-trash.err
+++ b/test/fix/header-trash.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the header checksum
+warning: Overwrote a non-zero byte in the header checksum
diff --git a/test/fix/header.err b/test/fix/header.err
index 5fa313aa..021584b6 100644
--- a/test/fix/header.err
+++ b/test/fix/header.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the header checksum
+warning: Overwrote a non-zero byte in the header checksum
diff --git a/test/fix/jp.err b/test/fix/jp.err
index 73328e27..21b5612c 100644
--- a/test/fix/jp.err
+++ b/test/fix/jp.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the destination code
+warning: Overwrote a non-zero byte in the destination code
diff --git a/test/fix/logo-trash.err b/test/fix/logo-trash.err
index 41ef05b1..b8822a17 100644
--- a/test/fix/logo-trash.err
+++ b/test/fix/logo-trash.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the Nintendo logo
+warning: Overwrote a non-zero byte in the Nintendo logo
diff --git a/test/fix/logo.err b/test/fix/logo.err
index 41ef05b1..b8822a17 100644
--- a/test/fix/logo.err
+++ b/test/fix/logo.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the Nintendo logo
+warning: Overwrote a non-zero byte in the Nintendo logo
diff --git a/test/fix/new-lic.err b/test/fix/new-lic.err
index a5726611..490edc34 100644
--- a/test/fix/new-lic.err
+++ b/test/fix/new-lic.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the new licensee code
+warning: Overwrote a non-zero byte in the new licensee code
diff --git a/test/fix/old-lic-hex.err b/test/fix/old-lic-hex.err
index 113f98fc..6be69743 100644
--- a/test/fix/old-lic-hex.err
+++ b/test/fix/old-lic-hex.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the old licensee code
+warning: Overwrote a non-zero byte in the old licensee code
diff --git a/test/fix/old-lic.err b/test/fix/old-lic.err
index 113f98fc..6be69743 100644
--- a/test/fix/old-lic.err
+++ b/test/fix/old-lic.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the old licensee code
+warning: Overwrote a non-zero byte in the old licensee code
diff --git a/test/fix/ram.err b/test/fix/ram.err
index 76d799b7..1dcebcee 100644
--- a/test/fix/ram.err
+++ b/test/fix/ram.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the RAM size
+warning: Overwrote a non-zero byte in the RAM size
diff --git a/test/fix/ramful-mbc.err b/test/fix/ramful-mbc.err
index 35ef63d9..dfa76d9b 100644
--- a/test/fix/ramful-mbc.err
+++ b/test/fix/ramful-mbc.err
@@ -1,2 +1,2 @@
-warning: Overwrote a non-zero byte in the cartridge type
-warning: Overwrote a non-zero byte in the RAM size
+warning: Overwrote a non-zero byte in the cartridge type
+warning: Overwrote a non-zero byte in the RAM size
diff --git a/test/fix/ramless-mbc.err b/test/fix/ramless-mbc.err
index 35ef63d9..dfa76d9b 100644
--- a/test/fix/ramless-mbc.err
+++ b/test/fix/ramless-mbc.err
@@ -1,2 +1,2 @@
-warning: Overwrote a non-zero byte in the cartridge type
-warning: Overwrote a non-zero byte in the RAM size
+warning: Overwrote a non-zero byte in the cartridge type
+warning: Overwrote a non-zero byte in the RAM size
diff --git a/test/fix/sgb.err b/test/fix/sgb.err
index 3c4caeaa..1e8cc8f4 100644
--- a/test/fix/sgb.err
+++ b/test/fix/sgb.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the SGB flag
+warning: Overwrote a non-zero byte in the SGB flag
diff --git a/test/fix/test.sh b/test/fix/test.sh
index 360ef758..7fd5cbeb 100755
--- a/test/fix/test.sh
+++ b/test/fix/test.sh
@@ -25,7 +25,7 @@ rescolors="$(tput op)"
 RGBFIX=./rgbfix
 
 tryDiff () {
-	if ! diff -u --strip-trailing-cr "$1" "$2"; then
+	if ! diff -au --strip-trailing-cr "$1" "$2"; then
 		echo "${bold}${red}${3:-$1} mismatch!${rescolors}${resbold}"
 		false
 	fi
diff --git a/test/fix/title-pad.err b/test/fix/title-pad.err
index 8d4a2b4e..c67f1407 100644
--- a/test/fix/title-pad.err
+++ b/test/fix/title-pad.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the title
+warning: Overwrote a non-zero byte in the title
diff --git a/test/fix/title.err b/test/fix/title.err
index 8d4a2b4e..c67f1407 100644
--- a/test/fix/title.err
+++ b/test/fix/title.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the title
+warning: Overwrote a non-zero byte in the title
diff --git a/test/fix/verify-pad.err b/test/fix/verify-pad.err
index 24fa0195..9f90148f 100644
--- a/test/fix/verify-pad.err
+++ b/test/fix/verify-pad.err
@@ -1,3 +1,3 @@
-warning: Overwrote a non-zero byte in the Nintendo logo
-warning: Overwrote a non-zero byte in the header checksum
-warning: Overwrote a non-zero byte in the global checksum
+warning: Overwrote a non-zero byte in the Nintendo logo
+warning: Overwrote a non-zero byte in the header checksum
+warning: Overwrote a non-zero byte in the global checksum
diff --git a/test/fix/verify-trash.err b/test/fix/verify-trash.err
index 24fa0195..9f90148f 100644
--- a/test/fix/verify-trash.err
+++ b/test/fix/verify-trash.err
@@ -1,3 +1,3 @@
-warning: Overwrote a non-zero byte in the Nintendo logo
-warning: Overwrote a non-zero byte in the header checksum
-warning: Overwrote a non-zero byte in the global checksum
+warning: Overwrote a non-zero byte in the Nintendo logo
+warning: Overwrote a non-zero byte in the header checksum
+warning: Overwrote a non-zero byte in the global checksum
diff --git a/test/fix/verify.err b/test/fix/verify.err
index 24fa0195..9f90148f 100644
--- a/test/fix/verify.err
+++ b/test/fix/verify.err
@@ -1,3 +1,3 @@
-warning: Overwrote a non-zero byte in the Nintendo logo
-warning: Overwrote a non-zero byte in the header checksum
-warning: Overwrote a non-zero byte in the global checksum
+warning: Overwrote a non-zero byte in the Nintendo logo
+warning: Overwrote a non-zero byte in the header checksum
+warning: Overwrote a non-zero byte in the global checksum
diff --git a/test/fix/version.err b/test/fix/version.err
index a882d2c6..efd4d92a 100644
--- a/test/fix/version.err
+++ b/test/fix/version.err
@@ -1 +1 @@
-warning: Overwrote a non-zero byte in the mask ROM version number
+warning: Overwrote a non-zero byte in the mask ROM version number
diff --git a/test/gfx/test.sh b/test/gfx/test.sh
index 3b54f034..7896b630 100755
--- a/test/gfx/test.sh
+++ b/test/gfx/test.sh
@@ -83,7 +83,7 @@ for f in *.png; do
 	newTest "$RGBGFX" $flags "$f"
 	if [[ -e "${f%.png}.err" ]]; then
 		runTest 2>"$errtmp"
-		diff -u --strip-trailing-cr "${f%.png}.err" "$errtmp" || failTest
+		diff -au --strip-trailing-cr "${f%.png}.err" "$errtmp" || failTest
 	else
 		runTest && checkOutput "${f%.png}" || failTest $?
 	fi
@@ -91,7 +91,7 @@ for f in *.png; do
 	newTest "$RGBGFX" $flags - "<$f"
 	if [[ -e "${f%.png}.err" ]]; then
 		runTest 2>"$errtmp"
-		diff -u --strip-trailing-cr <(sed "s/$f/<stdin>/g" "${f%.png}.err") "$errtmp" || failTest
+		diff -au --strip-trailing-cr <(sed "s/$f/<stdin>/g" "${f%.png}.err") "$errtmp" || failTest
 	else
 		runTest && checkOutput "${f%.png}" || failTest $?
 	fi
diff --git a/test/link/test.sh b/test/link/test.sh
index 4e3a07f9..db9bae04 100755
--- a/test/link/test.sh
+++ b/test/link/test.sh
@@ -38,7 +38,7 @@ continueTest () {
 }
 
 tryDiff () {
-	if ! diff -u --strip-trailing-cr "$1" "$2"; then
+	if ! diff -au --strip-trailing-cr "$1" "$2"; then
 		echo "${bold}${red}$1 mismatch!${rescolors}${resbold}"
 		false
 	fi