refactor the tests of options (#16527)

tests/stdlib/toptions.nim

@@ -1,19 +1,8 @@
 discard """
-  output: '''{"foo":{"test":"123"}}'''
+  targets: "c js"
 """
 
-import json, options
+import std/[json, options]
-
-type
-  Foo = ref object
-    test: string
-  Test = object
-    foo: Option[Foo]
-
-let js = """{"foo": {"test": "123"}}"""
-let parsed = parseJson(js)
-let a = parsed.to(Test)
-echo $(%*a)
 
 
 # RefPerson is used to test that overloaded `==` operator is not called by
@@ -26,6 +15,27 @@ proc `==`(a, b: RefPerson): bool =
   assert(not a.isNil and not b.isNil)
   a.name == b.name
 
+
+template disableJsVm(body) =
+  # something doesn't work in JS VM
+  when defined(js):
+    when nimvm: discard
+    else: body
+  else:
+    body
+
+proc main() =
+  type
+    Foo = ref object
+      test: string
+    Test = object
+      foo: Option[Foo]
+
+  let js = """{"foo": {"test": "123"}}"""
+  let parsed = parseJson(js)
+  let a = parsed.to(Test)
+  doAssert $(%*a) == """{"foo":{"test":"123"}}"""
+
   block options:
     # work around a bug in unittest
     let intNone = none(int)
@@ -75,8 +85,11 @@ block options:
       doAssert($(some("Correct")) == "Some(\"Correct\")")
       doAssert($(stringNone) == "None[string]")
 
+    disableJsVm:
       block map_with_a_void_result:
         var procRan = 0
+        # TODO closure anonymous functions doesn't work in VM with JS
+        # Error: cannot evaluate at compile time: procRan
         some(123).map(proc (v: int) = procRan = v)
         doAssert procRan == 123
         intNone.map(proc (v: int) = doAssert false)
@@ -156,3 +169,29 @@ block options:
     block:
       let p = some(RefPerson.new())
       doAssert p.isSome
+
+    block: # test cstring
+      block:
+        let x = some("".cstring)
+        doAssert x.isSome
+        doAssert x.get == ""
+
+      block:
+        let x = some("12345".cstring)
+        doAssert x.isSome
+        doAssert x.get == "12345"
+
+      block:
+        let x = "12345".cstring
+        let y = some(x)
+        doAssert y.isSome
+        doAssert y.get == "12345"
+
+      block:
+        let x = none(cstring)
+        doAssert x.isNone
+        doAssert $x == "None[cstring]"
+
+
+static: main()
+main()