Add test for objvariant construction order

Fixes #4665

1 files changed, 114 insertions, 0 deletions

diff --git a/tests/objvariant/tconstructionorder.nim b/tests/objvariant/tconstructionorder.nim
new file mode 100644
index 000000000..19ddea7a1
--- /dev/null
+++ b/tests/objvariant/tconstructionorder.nim
@@ -0,0 +1,114 @@
+discard """
+  output: "SUCCESS"
+"""
+
+# A test to ensure that the order in which a variant
+# object is constructed doesn't matter.
+
+type
+  NodeKind = enum
+    Literal, Operator
+
+  Node = ref object
+    case kind: NodeKind
+    of Literal:
+      value: int
+    of Operator:
+      left, right: Node
+      operator: char
+
+# The trees used through out this test should
+# be the same after construction, the only difference
+# being the way we specify their construction.
+# This will test that all the values are what we expect.
+proc assertTree(root: Node) =
+  # check root of tree
+  assert root.kind == Operator
+  assert root.operator == '*'
+
+  # check left subtree
+  assert root.left.value == 5
+  assert root.left.kind == Literal
+
+  # check right subtree
+  assert root.right.kind == Operator
+  assert root.right.operator == '+'
+
+  assert root.right.left.value == 5
+  assert root.right.left.kind == Literal
+
+  assert root.right.right.value == 10
+  assert root.right.right.kind == Literal
+
+proc newLiteralNode(value: int): Node =
+  result = Node(
+    kind: Literal,
+    value: value
+  )
+
+var rootOrder1 = Node(
+  kind: Operator,
+  operator: '*',
+  left: newLiteralNode(5),
+  right: Node(
+    left: newLiteralNode(5),
+    right: newLiteralNode(10),
+    kind: Operator,
+    operator: '+'
+  )
+)
+assertTree(rootOrder1)
+
+var rootOrder2 = Node(
+  operator: '*',
+  kind: Operator,
+  left: newLiteralNode(5),
+  right: Node(
+    left: newLiteralNode(5),
+    right: newLiteralNode(10),
+    kind: Operator,
+    operator: '+'
+  )
+)
+assertTree(rootOrder2)
+
+var rootOrder3 = Node(
+  left: newLiteralNode(5),
+  operator: '*',
+  kind: Operator,
+  right: Node(
+    left: newLiteralNode(5),
+    right: newLiteralNode(10),
+    kind: Operator,
+    operator: '+'
+  )
+)
+assertTree(rootOrder3)
+
+var rootOrder4 = Node(
+  left: newLiteralNode(5),
+  operator: '*',
+  kind: Operator,
+  right: Node(
+    left: newLiteralNode(5),
+    kind: Operator,
+    operator: '+',
+    right: newLiteralNode(10)
+  )
+)
+assertTree(rootOrder4)
+
+var rootOrder5 = Node(
+  left: newLiteralNode(5),
+  operator: '*',
+  kind: Operator,
+  right: Node(
+    left: newLiteralNode(5),
+    operator: '+',
+    right: newLiteralNode(10),
+    kind: Operator
+  )
+)
+assertTree(rootOrder5)
+
+echo "SUCCESS"