testsuite: Add formal tests (#57)

* Add formal tests for shift operations

* ci: build ghdl/synth:formal and run test suites in it

* add testsuite/formal/testsuite.sh

* create testsuite/issues

* ci: remove a level of grouping

* testenv: fix SYMBIYOSYS

* refactor

* testsuite/formal/shifts: Add check for shifts > vector length

1 files changed, 16 insertions, 0 deletions

diff --git a/testsuite/issues/issue4/no_vector.vhdl b/testsuite/issues/issue4/no_vector.vhdl
new file mode 100644
index 0000000..a3c2c46
--- /dev/null
+++ b/testsuite/issues/issue4/no_vector.vhdl
@@ -0,0 +1,16 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity no_vector is
+  port (led0: out std_logic);
+end no_vector;
+
+architecture synth of no_vector is
+
+signal nv : std_logic;
+
+begin
+  nv <= '1';
+  led0 <= nv;
+end synth;