Block contructor and tests

coordinator/tributary/src/provided.rs

@@ -0,0 +1,33 @@
+use std::collections::HashMap;
+
+use crate::{TransactionKind, Transaction};
+
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct ProvidedTransactions<T: Transaction> {
+  pub(crate) transactions: HashMap<[u8; 32], T>,
+}
+
+impl<T: Transaction> Default for ProvidedTransactions<T> {
+  fn default() -> Self {
+    ProvidedTransactions { transactions: HashMap::new() }
+  }
+}
+
+impl<T: Transaction> ProvidedTransactions<T> {
+  pub fn new() -> Self {
+    ProvidedTransactions::default()
+  }
+
+  /// Provide a transaction for inclusion in a block.
+  pub fn provide(&mut self, tx: T) {
+    assert_eq!(tx.kind(), TransactionKind::Provided, "provided a non-provided transaction");
+    self.transactions.insert(tx.hash(), tx);
+  }
+
+  /// Withdraw a transaction, no longer proposing it or voting for its validity.
+  ///
+  /// Returns true if the transaction was withdrawn and false otherwise.
+  pub fn withdraw(&mut self, tx: [u8; 32]) -> bool {
+    self.transactions.remove(&tx).is_some()
+  }
+}