Merge pull request #2 from logicalmechanism/adding-counters

count number of address inputs and outputs

lib/assist/count.ak

@@ -0,0 +1,121 @@
+//// This module includes code to count the number of inputs and outputs 
+//// associated with an address, typically a script address.
+////
+//// The amounts are assumed to be exact.
+
+use aiken/transaction.{Input, Output}
+use aiken/transaction/credential.{Address}
+use assist/addresses
+use tests/fake_tx
+
+/// Verify that the number of inputs from a specific script is equal the amount
+/// intended in the contract. The amount must be exact with the counter.
+///
+/// ```aiken
+/// script_inputs(tx.inputs, this_script_addr, 1)
+/// script_inputs(tx.inputs, that_script_addr, 2)
+/// ```
+pub fn script_inputs(
+  inputs: List<Input>,
+  script_addr: Address,
+  amount: Int,
+) -> Bool {
+  count_script_inputs(inputs, script_addr, 0) == amount
+}
+
+fn count_script_inputs(
+  inputs: List<Input>,
+  script_addr: Address,
+  counter: Int,
+) -> Int {
+  when inputs is {
+    [input, ..rest] ->
+      if input.output.address == script_addr {
+        count_script_inputs(rest, script_addr, counter + 1)
+      } else {
+        count_script_inputs(rest, script_addr, counter)
+      }
+    [] ->
+      counter
+  }
+}
+
+test single_script_input() {
+  let tx =
+    fake_tx.test_tx()
+  let addr =
+    addresses.create_address(#"acab", #"")
+  script_inputs(tx.inputs, addr, 1) == True
+}
+
+test not_enough_script_inputs() {
+  let tx =
+    fake_tx.test_tx()
+  let addr =
+    addresses.create_address(#"acab", #"")
+  script_inputs(tx.inputs, addr, 2) == False
+}
+
+test multiple_script_inputs() {
+  let tx =
+    fake_tx.test_tx()
+  let addr =
+    addresses.create_address(#"face", #"")
+  script_inputs(tx.inputs, addr, 2) == True
+}
+
+/// Verify that the number of outputs from a specific script is equal the amount
+/// intended in the contract. The amount must be exact with the counter.
+///
+/// ```aiken
+/// script_outputs(tx.outputs, this_script_addr, 1)
+/// script_outputs(tx.outputs, that_script_addr, 2)
+/// ```
+pub fn script_outputs(
+  outputs: List<Output>,
+  script_addr: Address,
+  amount: Int,
+) -> Bool {
+  count_script_outputs(outputs, script_addr, 0) == amount
+}
+
+fn count_script_outputs(
+  outputs: List<Output>,
+  script_addr: Address,
+  counter: Int,
+) -> Int {
+  when outputs is {
+    [output, ..rest] ->
+      if output.address == script_addr {
+        count_script_outputs(rest, script_addr, counter + 1)
+      } else {
+        count_script_outputs(rest, script_addr, counter)
+      }
+    [] ->
+      counter
+  }
+}
+
+test single_script_output() {
+  let tx =
+    fake_tx.test_tx()
+  let addr =
+    addresses.create_address(#"acab", #"")
+  script_outputs(tx.outputs, addr, 1) == True
+}
+
+test not_enough_script_outputs() {
+  let tx =
+    fake_tx.test_tx()
+  let addr =
+    addresses.create_address(#"acab", #"")
+  script_outputs(tx.outputs, addr, 2) == False
+}
+
+test multiple_script_outputs() {
+  let tx =
+    fake_tx.test_tx()
+  let addr =
+    addresses.create_address(#"face", #"")
+  script_outputs(tx.outputs, addr, 2) == True
+}

lib/assist/signing.ak

@@ -25,19 +25,19 @@ pub fn verify_sig(
 
 test no_signature() {
   let tx =
-    fake_tx.signature_only_tx()
+    fake_tx.test_tx()
   verify_sig(tx, #"") == False
 }
 
 test bad_signature() {
   let tx =
-    fake_tx.signature_only_tx()
+    fake_tx.test_tx()
   verify_sig(tx, #"cafe") == False
 }
 
 test has_signature() {
   let tx =
-    fake_tx.signature_only_tx()
+    fake_tx.test_tx()
   verify_sig(tx, #"acab") == True
 }
 
@@ -79,18 +79,18 @@ fn run_multisig(
 
 test no_multisig() {
   let tx =
-    fake_tx.signature_only_tx()
+    fake_tx.test_tx()
   verify_multisig(tx, [], 1) == False
 }
 
 test bad_multisig() {
   let tx =
-    fake_tx.signature_only_tx()
+    fake_tx.test_tx()
   verify_multisig(tx, [#"acab"], 2) == False
 }
 
 test has_multisig() {
   let tx =
-    fake_tx.signature_only_tx()
+    fake_tx.test_tx()
   verify_multisig(tx, [#"acab", #"beef"], 2) == True
 }

lib/tests/fake_tx.ak

@@ -1,14 +1,73 @@
 use aiken/dict
 use aiken/interval.{Interval, IntervalBound, NegativeInfinity, PositiveInfinity}
-use aiken/transaction.{Transaction, TransactionId}
+use aiken/transaction.{
+  Input, NoDatum, Output, OutputReference, Transaction, TransactionId,
+}
 use aiken/transaction/value
+use assist/addresses
 
-pub fn signature_only_tx() -> Transaction {
+pub fn test_tx() -> Transaction {
   let tx =
     Transaction {
-      inputs: [],
+      inputs: [
+        Input {
+          output_reference: OutputReference {
+            transaction_id: TransactionId { hash: #"" },
+            output_index: 0,
+          },
+          output: Output {
+            address: addresses.create_address(#"acab", #""),
+            value: value.from_lovelace(100),
+            datum: NoDatum,
+            reference_script: None,
+          },
+        },
+        Input {
+          output_reference: OutputReference {
+            transaction_id: TransactionId { hash: #"" },
+            output_index: 1,
+          },
+          output: Output {
+            address: addresses.create_address(#"face", #""),
+            value: value.from_lovelace(5),
+            datum: NoDatum,
+            reference_script: None,
+          },
+        },
+        Input {
+          output_reference: OutputReference {
+            transaction_id: TransactionId { hash: #"" },
+            output_index: 1,
+          },
+          output: Output {
+            address: addresses.create_address(#"face", #""),
+            value: value.from_lovelace(5),
+            datum: NoDatum,
+            reference_script: None,
+          },
+        },
+      ],
       reference_inputs: [],
-      outputs: [],
+      outputs: [
+        Output {
+          address: addresses.create_address(#"acab", #""),
+          value: value.from_asset(#"acab", #"beef", 40),
+          datum: NoDatum,
+          reference_script: None,
+        },
+        Output {
+          address: addresses.create_address(#"face", #""),
+          value: value.from_lovelace(40),
+          datum: NoDatum,
+          reference_script: None,
+        },
+        Output {
+          address: addresses.create_address(#"face", #""),
+          value: value.from_lovelace(60),
+          datum: NoDatum,
+          reference_script: None,
+        },
+      ],
       fee: value.zero(),
       mint: value.zero(),
       certificates: [],