diff --git a/Makefile b/Makefile
index 2c4c7ad..d648ba1 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CC = gcc
 CPPFLAGS = -Isrc/ -D_POSIX_C_SOURCE=200809L
-VPATH = src/
 CFLAGS = -Wall -Wextra -pedantic -Werror -std=c99
+VPATH = src/ tests/
 USE_CLIMBING = 1
 
 SRC = \
@@ -16,7 +16,20 @@ all: $(BIN)
 $(BIN):
 $(BIN): $(OBJ) src/pratt.o
 
+check: testsuite
+	./testsuite --verbose
+
+TEST_SRC = \
+    tests/testsuite.c \
+
+TEST_OBJ = $(TEST_SRC:.c=.o)
+
+testsuite: LDFLAGS+=-lcriterion -fsanitize=address
+testsuite: CFLAGS+=-fsanitize=address
+testsuite: $(OBJ) $(TEST_OBJ)
+
 .PHONY: clean
 clean:
 	$(RM) $(OBJ) # remove object files
 	$(RM) $(BIN) # remove main program
+	$(RM) testsuite
diff --git a/tests/testsuite.c b/tests/testsuite.c
new file mode 100644
index 0000000..7bb0dbe
--- /dev/null
+++ b/tests/testsuite.c
@@ -0,0 +1,76 @@
+#include <criterion/criterion.h>
+
+#include "eval.h"
+
+TestSuite(eval_string);
+
+static void do_success(const char *input, int exptected) {
+    int val;
+
+    cr_assert(eval_string(input, &val));
+    cr_assert_eq(val, exptected);
+}
+
+static void do_failure(const char *input) {
+    int val;
+
+    cr_assert_not(eval_string(input, &val));
+}
+
+#define SUCCESS(Name, Input) \
+    Test(eval_string, Name) { do_success(#Input, (Input)); }
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wparentheses"
+SUCCESS(one, 1)
+SUCCESS(the_answer, 42)
+SUCCESS(int_max, 2147483647)
+SUCCESS(addition, 1 + 2)
+SUCCESS(additions, 1 + 2 + 3 + 4)
+SUCCESS(substraction, 1 - 2)
+SUCCESS(substractions, 1 - 1 - 1)
+SUCCESS(multiplication, 2 * 3)
+SUCCESS(multiplications, 2 * 3 * 4)
+SUCCESS(division, 6 / 3)
+SUCCESS(divisions, 6 / 3 / 2)
+SUCCESS(modulo, 6 % 5)
+SUCCESS(modulos, 127 % 19 % 3)
+SUCCESS(left_shift, 1 << 3)
+SUCCESS(left_shift_not_one, 42 << 3)
+SUCCESS(right_shift, 1024 >> 3)
+SUCCESS(right_shift_not_one, 1337 >> 3)
+SUCCESS(eq, 1 == 1)
+SUCCESS(neq, 1 != 1)
+SUCCESS(not_true, !1)
+SUCCESS(not_false, !0)
+SUCCESS(bit_not, ~0)
+SUCCESS(bit_not_the_answer, ~42)
+SUCCESS(bit_and, 0 & 1)
+SUCCESS(bit_and_non_zero, 255 & 127)
+SUCCESS(bit_xor, 0 ^ 1)
+SUCCESS(bit_xor_non_zero, 255 ^ 127)
+SUCCESS(and, 1 && 0)
+SUCCESS(and_non_false, 1 && 2)
+SUCCESS(or, 0 || 1)
+SUCCESS(or_false, 0 || 0)
+SUCCESS(ternary_true, 1 ? 12 : 27)
+SUCCESS(ternary_false, 0 ? 12 : 27)
+SUCCESS(arith_priorities, 1 + 2 * 3 % 4 * 52 / 3)
+SUCCESS(parenthesis, (1 + 2) * 3)
+SUCCESS(shift_priorities, 1 + 2 << 5 - 3 >> 1)
+SUCCESS(bitwise_priorities, 3241235 ^ 1234 & 4321 | 94)
+SUCCESS(boolean_priorities, 1 == 3 & 1 | 2048)
+SUCCESS(ternary_priorities, 1 == 2 ? 1 << 3 - 1 >> 1 : 42 << 4)
+#pragma GCC diagnostic pop
+
+#define FAILURE(Name, Input) \
+    Test(eval_string, Name) { do_failure(Input); }
+
+FAILURE(empty, "")
+FAILURE(right_parenthesis, ")")
+FAILURE(empty_parenthesis, "()")
+FAILURE(trailing_operator, "1 +")
+FAILURE(trailing_expression, "1 1")
+FAILURE(double_operator, "1 * * 1")
+FAILURE(prefix_as_infix, "1 ! 1")
+FAILURE(infix_as_prefix, "*1")