diff --git a/testing/Makefile b/testing/Makefile
new file mode 100644
index 0000000..95d2efb
--- /dev/null
+++ b/testing/Makefile
@@ -0,0 +1,13 @@
+
+.SILENT:
+
+all:
+	echo "Testing CPUs..."
+	echo
+	make -C cpus
+	echo "Testing errors..."
+	echo
+	make -C errors
+	echo "Testing warnings..."
+	echo
+	make -C warnings
diff --git a/testing/cpus/Makefile b/testing/cpus/Makefile
new file mode 100644
index 0000000..613641c
--- /dev/null
+++ b/testing/cpus/Makefile
@@ -0,0 +1,17 @@
+ACMEFLAGS	= -v0
+CPUS	:= $(subst .a,,$(subst test-,,$(wildcard test-*.a)))
+FILES	= $(foreach N,$(CPUS),$(N).o)
+
+.SILENT:
+
+%.o: test-%.a
+	echo "Testing CPU:" $(subst .o,,$@)
+	acme $(ACMEFLAGS) -o test.o $<
+	cmp test.o expected-$@
+	rm test.o
+	echo "Ok."
+
+all: $(FILES)
+	echo
+	echo "Testing CPUs: PASSED"
+	echo
diff --git a/testing/cpus/check-all-cpus.sh b/testing/cpus/check-all-cpus.sh
deleted file mode 100755
index 05f3353..0000000
--- a/testing/cpus/check-all-cpus.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/bin/bash
-for CPU in 6502 65c02 r65c02 w65c02 nmos6502 c64dtv2 65ce02 4502 m65 65816 ; do
-	acme -v0 test-"$CPU".a || exit
-	cmp out-"$CPU".o expected-"$CPU".o || exit
-done
-echo
-echo "All CPU tests passed successfully."
-echo
diff --git a/testing/errors/Makefile b/testing/errors/Makefile
new file mode 100644
index 0000000..e957db9
--- /dev/null
+++ b/testing/errors/Makefile
@@ -0,0 +1,15 @@
+ACMEFLAGS	= -v0
+FILES	:= $(wildcard *.a)
+TESTS	= $(subst .a,.test,$(FILES))
+
+.SILENT:
+
+%.test: %.a
+	echo "Testing error generation:" $<
+	! acme $(ACMEFLAGS) $<
+	echo "Ok."
+
+all: $(TESTS)
+	echo
+	echo "Testing errors: PASSED"
+	echo
diff --git a/testing/errors/opnotsupp2.a b/testing/errors/opnotsupp2.a
new file mode 100644
index 0000000..4162f16
--- /dev/null
+++ b/testing/errors/opnotsupp2.a
@@ -0,0 +1 @@
+	a = 3 != []	; -> "Operation not supported."
diff --git a/testing/errors/opnotsupp3.a b/testing/errors/opnotsupp3.a
new file mode 100644
index 0000000..a68c914
--- /dev/null
+++ b/testing/errors/opnotsupp3.a
@@ -0,0 +1 @@
+	b = "str" = []	; -> "Operation not supported."
diff --git a/testing/errors/opnotsupp4.a b/testing/errors/opnotsupp4.a
new file mode 100644
index 0000000..b51bc70
--- /dev/null
+++ b/testing/errors/opnotsupp4.a
@@ -0,0 +1 @@
+	c = [] + 3	; -> "Operation not supported."
diff --git a/testing/errors/valuenotdefined3.a b/testing/errors/valuenotdefined3.a
new file mode 100644
index 0000000..a9eda7a
--- /dev/null
+++ b/testing/errors/valuenotdefined3.a
@@ -0,0 +1,2 @@
+	* = $200
+	!by .local	; -> "Value not defined."
diff --git a/testing/errors/valuenotdefined4.a b/testing/errors/valuenotdefined4.a
new file mode 100644
index 0000000..3fded8a
--- /dev/null
+++ b/testing/errors/valuenotdefined4.a
@@ -0,0 +1,2 @@
+	* = $200
+	!by @cheap_local	; -> "Value not defined."
diff --git a/testing/warnings/Makefile b/testing/warnings/Makefile
new file mode 100644
index 0000000..6696a06
--- /dev/null
+++ b/testing/warnings/Makefile
@@ -0,0 +1,21 @@
+ACMEFLAGS	= -v0
+FILES		:= $(wildcard *.a)
+FAILTESTS	= $(subst .a,.fail,$(FILES))
+SUCCTESTS	= $(subst .a,.succ,$(FILES))
+
+.SILENT:
+
+%.fail: %.a
+	echo "Testing warning with --strict:" $<
+	! acme $(ACMEFLAGS) --strict $<
+	echo "Ok."
+
+%.succ: %.a
+	echo "Testing warning:" $<
+	acme $(ACMEFLAGS) $<
+	echo "Ok."
+
+all: $(FAILTESTS) $(SUCCTESTS)
+	echo
+	echo "Testing warnings: PASSED"
+	echo
diff --git a/testing/warnings/initmem.a b/testing/warnings/initmem.a
new file mode 100644
index 0000000..0b78669
--- /dev/null
+++ b/testing/warnings/initmem.a
@@ -0,0 +1,2 @@
+	!initmem 0
+	!initmem 0	; -> "Memory already initialised."
diff --git a/testing/warnings/limit.a b/testing/warnings/limit.a
new file mode 100644
index 0000000..767022d
--- /dev/null
+++ b/testing/warnings/limit.a
@@ -0,0 +1,6 @@
+	*=$1000
+	!tx "Hinz"
+	!outfilelimit
+	!tx "Kunz"
+	!outfilelimit	; -> "End of output file already chosen."
+	!tx "Bla"
diff --git a/testing/warnings/segment1.a b/testing/warnings/segment1.a
new file mode 100644
index 0000000..b21cd02
--- /dev/null
+++ b/testing/warnings/segment1.a
@@ -0,0 +1,6 @@
+	*=$1000
+		clc
+		nop
+		rts
+	*=$1001
+		brk	; -> "Segment starts inside another one, overwriting it."
diff --git a/testing/warnings/segment2.a b/testing/warnings/segment2.a
new file mode 100644
index 0000000..0de1a46
--- /dev/null
+++ b/testing/warnings/segment2.a
@@ -0,0 +1,6 @@
+	*=$1001
+		brk
+	*=$1000
+		clc
+		nop	; -> "Segment reached another one, overwriting it."
+		rts
diff --git a/testing/warnings/start.a b/testing/warnings/start.a
new file mode 100644
index 0000000..9ff9690
--- /dev/null
+++ b/testing/warnings/start.a
@@ -0,0 +1,6 @@
+	*=$1000
+	!tx "Hinz"
+	!outfilestart
+	!tx "Kunz"
+	!outfilestart	; -> "Start of output file already chosen."
+	!tx "Bla"