Add previous sh tests in bats

test.bats

@@ -4,3 +4,49 @@
     result="$(echo '42=' | ./eval.out)"
     [ "$result" = "42" ]
 }
+
+@test "Basic addition" {
+	result="$(echo '1+2=' | ./eval.out)"
+	[ "$result" = "3" ]
+}
+
+@test "Basic substraction" {
+	result="$(echo '1-2=' | ./eval.out)"
+	[ "$result" = "-1" ]
+}
+
+@test "Multiplication priority over addition" {
+	result="$(echo '1+2*3=' | ./eval.out)"
+	[ "$result" = "7" ]
+}
+
+@test "Parenthesis priority" {
+	result="$(echo '(1+2)*3=' | ./eval.out)"
+	[ "$result" = "9" ]
+}
+
+@test "Three operands with addition" {
+	result="$(echo '1+2+3=' | ./eval.out)"
+	[ "$result" = "6" ]
+}
+
+@test "Two parenthesis blocks" {
+	result="$(echo '(1 - 1) + (2 - 2) =' | ./eval.out)"
+	[ "$result" = "0" ]
+}
+
+@test "Addition, substraction and multiplication" {
+	result="$(echo '1 + 7 - 4 * 2 =' | ./eval.out)"
+	[ "$result" = "0" ]
+}
+
+@test "Basic division" {
+	result="$(echo '42 / 7 =' | ./eval.out)"
+	[ "$result" = "6" ]
+}
+
+@test "Basic truncated division" {
+	result="$(echo '16 / 3 =' | ./eval.out)"
+	[ "$result" = "5" ]
+}
+