diff --git a/tests/images/customize.sh b/tests/images/customize.sh
index ae55a9307..8d1aa4bf8 100755
--- a/tests/images/customize.sh
+++ b/tests/images/customize.sh
@@ -145,45 +145,118 @@ qemu_disk() {
 }
 
 assert() {
-    grep -Fq "$1" log
+    if grep -Fq "$1" log; then
+        echo "Assertion passed: '$1' found in log"
+        return 0
+    else
+        echo "Assertion failed: '$1' not found in log"
+        return 1
+    fi
+}
+
+assert() {
+   grep -Fq "$1" log
+}
+
+assert_not() {
+    if grep -Fq "$1" log; then
+        return 1
+    else
+        return 0
+    fi
 }
 
 check_live_noinstall() {
-    assert @applied-live-ign@
-    assert @applied-live-2-ign@
-    ! assert @applied-dest-ign@
-    ! assert @applied-dest-2-ign@
-    assert @did-not-install@
-    ! assert @preinst-1@
-    ! assert @preinst-2@
-    ! assert @postinst-1@
-    ! assert @postinst-2@
-    assert 'Adding "coreos-installer test certificate" to list of CAs'
+    echo "Checking assertion: @applied-live-ign@"
+    assert @applied-live-ign@ || { echo "Failed assertion: @applied-live-ign@"; return 1; }
+
+    echo "Checking assertion: @applied-live-2-ign@"
+    assert @applied-live-2-ign@ || { echo "Failed assertion: @applied-live-2-ign@"; return 1; }
+
+    echo "Checking assertion: @applied-dest-ign@ should not be present"
+    assert_not @applied-dest-ign@ || { echo "Failed assertion: @applied-dest-ign@ should not be present"; return 1; }
+
+    echo "Checking assertion: @applied-dest-2-ign@ should not be present"
+    assert_not @applied-dest-2-ign@ || { echo "Failed assertion: @applied-dest-2-ign@ should not be present"; return 1; }
+
+    echo "Checking assertion: @did-not-install@"
+    assert @did-not-install@ || { echo "Failed assertion: @did-not-install@"; return 1; }
+
+    echo "Checking assertion: @preinst-1@ should not be present"
+    assert_not @preinst-1@ || { echo "Failed assertion: @preinst-1@ should not be present"; return 1; }
+
+    echo "Checking assertion: @preinst-2@ should not be present"
+    assert_not @preinst-2@ || { echo "Failed assertion: @preinst-2@ should not be present"; return 1; }
+
+    echo "Checking assertion: @postinst-1@ should not be present"
+    assert_not @postinst-1@ || { echo "Failed assertion: @postinst-1@ should not be present"; return 1; }
+
+    echo "Checking assertion: @postinst-2@ should not be present"
+    assert_not @postinst-2@ || { echo "Failed assertion: @postinst-2@ should not be present"; return 1; }
+
+    echo 'Checking assertion: Adding "coreos-installer test certificate" to list of CAs'
+    assert 'Adding "coreos-installer test certificate" to list of CAs' || { echo 'Failed assertion: Adding "coreos-installer test certificate" to list of CAs'; return 1; }
 }
 
 check_live_install() {
-    assert @applied-live-ign@
-    assert @applied-live-2-ign@
-    ! assert @applied-dest-ign@
-    ! assert @applied-dest-2-ign@
-    ! assert @did-not-install@
-    assert @preinst-1@
-    assert @preinst-2@
-    assert @postinst-1@
-    assert @postinst-2@
-    assert 'Adding "coreos-installer test certificate" to list of CAs'
+    echo "Checking assertion: @applied-live-ign@"
+    assert @applied-live-ign@ || { echo "Failed assertion: @applied-live-ign@"; return 1; }
+
+    echo "Checking assertion: @applied-live-2-ign@"
+    assert @applied-live-2-ign@ || { echo "Failed assertion: @applied-live-2-ign@"; return 1; }
+
+    echo "Checking assertion: @applied-dest-ign@ should not be present"
+    assert_not @applied-dest-ign@ || { echo "Failed assertion: @applied-dest-ign@ should not be present"; return 1; }
+
+    echo "Checking assertion: @applied-dest-2-ign@ should not be present"
+    assert_not @applied-dest-2-ign@ || { echo "Failed assertion: @applied-dest-2-ign@ should not be present"; return 1; }
+
+    echo "Checking assertion: @did-not-install@ should not be present"
+    assert_not @did-not-install@ || { echo "Failed assertion: @did-not-install@ should not be present"; return 1; }
+
+    echo "Checking assertion: @preinst-1@"
+    assert @preinst-1@ || { echo "Failed assertion: @preinst-1@"; return 1; }
+
+    echo "Checking assertion: @preinst-2@"
+    assert @preinst-2@ || { echo "Failed assertion: @preinst-2@"; return 1; }
+
+    echo "Checking assertion: @postinst-1@"
+    assert @postinst-1@ || { echo "Failed assertion: @postinst-1@"; return 1; }
+
+    echo "Checking assertion: @postinst-2@"
+    assert @postinst-2@ || { echo "Failed assertion: @postinst-2@"; return 1; }
+
+    echo 'Checking assertion: Adding "coreos-installer test certificate" to list of CAs'
+    assert 'Adding "coreos-installer test certificate" to list of CAs' || { echo 'Failed assertion: Adding "coreos-installer test certificate" to list of CAs'; return 1; }
 }
 
 check_dest() {
-    ! assert @applied-live-ign@
-    ! assert @applied-live-2-ign@
-    assert @applied-dest-ign@
-    assert @applied-dest-2-ign@
-    ! assert @preinst-1@
-    ! assert @preinst-2@
-    ! assert @postinst-1@
-    ! assert @postinst-2@
-    assert 'Adding "coreos-installer test certificate" to list of CAs'
+    echo "Checking assertion: @applied-live-ign@ should not be present"
+    assert_not @applied-live-ign@ || { echo "Failed assertion: @applied-live-ign@ should not be present"; return 1; }
+
+    echo "Checking assertion: @applied-live-2-ign@ should not be present"
+    assert_not @applied-live-2-ign@ || { echo "Failed assertion: @applied-live-2-ign@ should not be present"; return 1; }
+
+    echo "Checking assertion: @applied-dest-ign@"
+    assert @applied-dest-ign@ || { echo "Failed assertion: @applied-dest-ign@"; return 1; }
+
+    echo "Checking assertion: @applied-dest-2-ign@"
+    assert @applied-dest-2-ign@ || { echo "Failed assertion: @applied-dest-2-ign@"; return 1; }
+
+    echo "Checking assertion: @preinst-1@ should not be present"
+    assert_not @preinst-1@ || { echo "Failed assertion: @preinst-1@ should not be present"; return 1; }
+
+    echo "Checking assertion: @preinst-2@ should not be present"
+    assert_not @preinst-2@ || { echo "Failed assertion: @preinst-2@ should not be present"; return 1; }
+
+    echo "Checking assertion: @postinst-1@ should not be present"
+    assert_not @postinst-1@ || { echo "Failed assertion: @postinst-1@ should not be present"; return 1; }
+
+    echo "Checking assertion: @postinst-2@ should not be present"
+    assert_not @postinst-2@ || { echo "Failed assertion: @postinst-2@ should not be present"; return 1; }
+
+    echo 'Checking assertion: Adding "coreos-installer test certificate" to list of CAs'
+    assert 'Adding "coreos-installer test certificate" to list of CAs' || { echo 'Failed assertion: Adding "coreos-installer test certificate" to list of CAs'; return 1; }
 }
 
 # Check equivalence of ISO outputs