test(lua): add justification API tests

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

tests/lua/jst1.lua

@@ -0,0 +1,33 @@
+assert(is_justification(justification()))
+assert(justification():is_none())
+assert(justification("simple"):is_asserted())
+local env = empty_environment()
+local f = Const("f")
+local g = Const("g")
+local a = Const("a")
+local j1 = justification("expression must be a type", env, f(f(a)))
+assert(j1:is_asserted())
+print(j1:pp())
+local m  = mk_metavar("m", Bool)
+local j2 = justification("expresion must be a Proposition", env, g(m))
+print(j2:pp())
+local s  = substitution()
+s = s:assign(m, f(a))
+print(j2:pp(s))
+local j3 = assumption_justification(1)
+assert(not j2:depends_on(1))
+assert(j3:depends_on(1))
+assert(not j3:depends_on(2))
+local j4 = assumption_justification(2)
+assert(j4:depends_on(2))
+assert(not j4:depends_on(1))
+assert(j4:is_assumption())
+assert(not j4:main_expr())
+assert(j4:assumption_idx() == 2)
+local j5 = mk_composite_justification(mk_composite_justification(j1, j4), j3)
+assert(j5:depends_on(1))
+assert(j5:depends_on(2))
+assert(not j5:depends_on(3))
+assert(j5:is_composite())
+assert(j5:child2():is_eqp(j3))
+assert(j5:child1():child2():is_eqp(j4))