diff --git a/tests/do_tests.sh b/tests/do_tests.sh
index 2b0f5a1..2868454 100755
--- a/tests/do_tests.sh
+++ b/tests/do_tests.sh
@@ -4,7 +4,7 @@ unset CDPATH
 tests_dir=$(dirname $(readlink -f $0))
 cd "$tests_dir"
 
-trap 'rm -fr tmp.* a.out' EXIT INT TERM
+trap 'rm -fr tmp* a.out' EXIT INT TERM
 
 # some values reported in errors are not determinate (e.g. variable addresses)
 # and will vary between execution and definitely between platforms
@@ -35,7 +35,7 @@ mkdir -p $expected_output_dir
 test_failed=0
 
 # don't change the variable src_file some tests rely on it
-for src_file in tests/extracted_compile_time_tests/*.c tests/compile_time/*.c tests/run_time/*.c
+for src_file in tests/extracted_compile_time_tests/*.c tests/compile_time/*.c tests/run_time/*.*
 do
 	rm -f a.out
 
@@ -44,13 +44,21 @@ do
 
 	for compile_options in $compile_options_list
 	do
-		dcc_flags=
-		suffix=`echo $compile_options|sed 's/^dcc_flags=//;s/["$]//g;s/src_file//'`
-		eval $compile_options
-		expected_stderr_file="$expected_output_dir/`basename $src_file .c`$suffix.txt"
-		#echo "$dcc" --c-compiler=$c_compiler $dcc_flags "$src_file"
-		"$dcc" --c-compiler=$c_compiler $dcc_flags "$src_file" 2>tmp.actual_stderr >/dev/null
-		test ! -s tmp.actual_stderr && ./a.out </dev/null   2>>tmp.actual_stderr >/dev/null
+		case "$src_file" in
+		*.c)
+			dcc_flags=
+			suffix=`echo $compile_options|sed 's/^dcc_flags=//;s/["$]//g;s/src_file//'`
+			eval $compile_options
+			expected_stderr_file="$expected_output_dir/`basename $src_file .c`$suffix.txt"
+			#echo "$dcc" --c-compiler=$c_compiler $dcc_flags "$src_file"
+			"$dcc" --c-compiler=$c_compiler $dcc_flags "$src_file" 2>tmp.actual_stderr >/dev/null
+			test ! -s tmp.actual_stderr && ./a.out </dev/null   2>>tmp.actual_stderr >/dev/null
+			;;
+
+		*.sh)
+			expected_stderr_file="$expected_output_dir/`basename $src_file .sh`.txt"
+			$src_file </dev/null   2>tmp.actual_stderr >/dev/null
+		esac
 		
 		if test ! -s tmp.actual_stderr
 		then
diff --git a/tests/expected_output/clang-7.0-x86_64-pc-linux-gnu/incremental_compilation.txt b/tests/expected_output/clang-7.0-x86_64-pc-linux-gnu/incremental_compilation.txt
new file mode 100644
index 0000000..d44a7eb
--- /dev/null
+++ b/tests/expected_output/clang-7.0-x86_64-pc-linux-gnu/incremental_compilation.txt
@@ -0,0 +1,2 @@
+incremental compilation works
+incremental compilation works
diff --git a/tests/expected_output/clang-7.0-x86_64-pc-linux-gnu/uninitialized-array-element-if--valgrind.txt b/tests/expected_output/clang-7.0-x86_64-pc-linux-gnu/uninitialized-array-element-if--valgrind.txt
index 33381ad..69d2b9b 100644
--- a/tests/expected_output/clang-7.0-x86_64-pc-linux-gnu/uninitialized-array-element-if--valgrind.txt
+++ b/tests/expected_output/clang-7.0-x86_64-pc-linux-gnu/uninitialized-array-element-if--valgrind.txt
@@ -11,6 +11,7 @@ Execution stopped here in main() in tests/run_time/uninitialized-array-element-i
 
 Values when execution stopped:
 
+a =  <deleted-value>
 argc =  <deleted-value>
 a[42] =  <deleted-value>
 a[43] =  <deleted-value>
diff --git a/tests/run_time/incremental_compilation.sh b/tests/run_time/incremental_compilation.sh
new file mode 100755
index 0000000..fc12db2
--- /dev/null
+++ b/tests/run_time/incremental_compilation.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+cat >tmp1.c <<eof
+#include <stdio.h>
+void f(void) {fprintf(stderr, "incremental compilation works\n"); }
+eof
+
+cat >tmp2.c <<eof
+extern void f(void);
+int main(void) {f(); }
+eof
+
+dcc -c tmp1.c
+dcc -c tmp2.c
+dcc tmp1.o tmp2.o 
+./a.out
+dcc tmp1.o tmp2.c 
+./a.out