diff --git a/test/err/Makefile b/test/err/Makefile
index f0fcf3486..40ccfcb59 100644
--- a/test/err/Makefile
+++ b/test/err/Makefile
@@ -19,14 +19,15 @@ WORKDIR := ./../../testwrk
 
 .PHONY: all clean
 
-TESTS := $(patsubst %.c,$(WORKDIR)/%.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.o.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.os.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.or.prg,$(wildcard *.c))
+SOURCES := $(wildcard *.c)
+TESTS := $(SOURCES:%.c=$(WORKDIR)/%.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.o.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.os.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.or.prg)
 
 all: $(TESTS)
 
@@ -48,4 +49,4 @@ $(WORKDIR)/%.or.prg: %.c
 	! $(CL65) -Or $(CC65FLAGS) $< -o $@
 clean:
 	@$(RM) $(TESTS)
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.o,$(wildcard *.c))
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.o)
diff --git a/test/misc/Makefile b/test/misc/Makefile
index 0fa550d3f..b18d9165e 100644
--- a/test/misc/Makefile
+++ b/test/misc/Makefile
@@ -23,14 +23,15 @@ DIFF := $(WORKDIR)/bdiff
 
 .PHONY: all clean
 
-TESTS := $(patsubst %.c,$(WORKDIR)/%.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.o.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.os.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.or.prg,$(wildcard *.c))
+SOURCES := $(wildcard *.c)
+TESTS := $(SOURCES:%.c=$(WORKDIR)/%.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.o.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.os.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.or.prg)
 
 # FIXME: actually use/build differently optimized programs here
 
@@ -60,7 +61,7 @@ $(WORKDIR)/sitest%prg: sitest.c
 
 clean:
 	@$(RM) $(TESTS)
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.o,$(wildcard *.c))
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.out,$(wildcard *.c))
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.o)
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.out)
 
 
diff --git a/test/ref/Makefile b/test/ref/Makefile
index 2a465b500..b752adc1d 100644
--- a/test/ref/Makefile
+++ b/test/ref/Makefile
@@ -28,14 +28,15 @@ CFLAGS := -O2 -Wall -W -Wextra -fwrapv -fno-strict-overflow
 
 REFS := $(patsubst %.c,$(WORKDIR)/%.ref,$(wildcard *.c))
 
-TESTS := $(patsubst %.c,$(WORKDIR)/%.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.o.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.os.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.or.prg,$(wildcard *.c))
+SOURCES := $(wildcard *.c)
+TESTS := $(SOURCES:%.c=$(WORKDIR)/%.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.o.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.os.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.or.prg)
 
 all: $(REFS) $(TESTS)
 
@@ -85,7 +86,7 @@ $(WORKDIR)/%.or.prg: %.c $(WORKDIR)/%.ref
 
 clean:
 	@$(RM) $(TESTS)
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.o,$(wildcard *.c))
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.out,$(wildcard *.c))
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.ref,$(wildcard *.c))
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.host,$(wildcard *.c))
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.o)
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.out)
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.ref)
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.host)
diff --git a/test/val/Makefile b/test/val/Makefile
index 2dc4796e6..2e0aca278 100644
--- a/test/val/Makefile
+++ b/test/val/Makefile
@@ -21,14 +21,15 @@ WORKDIR := ./../../testwrk
 
 .PHONY: all clean
 
-TESTS := $(patsubst %.c,$(WORKDIR)/%.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.o.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.os.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.osir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oi.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.oir.prg,$(wildcard *.c))
-TESTS += $(patsubst %.c,$(WORKDIR)/%.or.prg,$(wildcard *.c))
+SOURCES := $(wildcard *.c)
+TESTS := $(SOURCES:%.c=$(WORKDIR)/%.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.o.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.os.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.osir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oi.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.oir.prg)
+TESTS += $(SOURCES:%.c=$(WORKDIR)/%.or.prg)
 
 all: $(TESTS)
 
@@ -66,4 +67,4 @@ $(WORKDIR)/%.or.prg: %.c
 
 clean:
 	@$(RM) $(TESTS)
-	@$(RM) $(patsubst %.c,$(WORKDIR)/%.o,$(wildcard *.c))
+	@$(RM) $(SOURCES:%.c=$(WORKDIR)/%.o)