test: cover element type discriminant 20

grovedb-element/src/element_type.rs

@@ -177,7 +177,7 @@ pub enum ProofNodeType {
 
 /// Element type discriminants.
 ///
-/// Base types (0..=14, 18, 19) match the bincode serialization order of
+/// Base types (0..=14, 18..=20) match the bincode serialization order of
 /// the `Element` enum. The `Element` enum has indices 15, 16, and 17
 /// reserved for the `NonCounted`, `NotSummed`, and `NotCountedOrSummed`
 /// wrapper variants respectively (none has a direct `ElementType`
@@ -228,7 +228,7 @@ pub enum ProofNodeType {
 /// and `from_serialized_value` resolves `[16, inner_byte]` to the matching
 /// twin via an explicit `inner_byte → twin` match.
 ///
-/// IMPORTANT: Base values (0..=14, 18, 19) must match the order of
+/// IMPORTANT: Base values (0..=14, 18..=20) must match the order of
 /// variants in the `Element` enum. The
 /// `test_element_serialization_discriminants_match_element_type` test
 /// catches drift.
@@ -1709,7 +1709,7 @@ mod tests {
 
         let grove_version = GroveVersion::latest();
 
-        // Build vector of (Element, ElementType, variant_name) for all 10 variants
+        // Build vector of (Element, ElementType, variant_name) for all base variants.
         let test_cases: Vec<(Element, ElementType, &str)> = vec![
             // discriminant 0
             (
@@ -1810,16 +1810,22 @@ mod tests {
                 ElementType::ProvableSumTree,
                 "ProvableSumTree",
             ),
+            // discriminant 20
+            (
+                Element::ProvableCountProvableSumTree(None, 0, 0, None),
+                ElementType::ProvableCountProvableSumTree,
+                "ProvableCountProvableSumTree",
+            ),
         ];
 
-        // Verify we're testing all 17 base discriminants: 0..=14, 18, 19.
+        // Verify we're testing all 18 base discriminants: 0..=14, 18..=20.
         // (15 = NonCounted wrapper byte, 16 = NotSummed wrapper byte,
         // 17 = NotCountedOrSummed wrapper byte — none has a base
         // ElementType variant.)
         assert_eq!(
             test_cases.len(),
-            17,
-            "Expected 17 base Element variants in test, got {}",
+            18,
+            "Expected 18 base Element variants in test, got {}",
             test_cases.len()
         );