(add): inter-canister-calls example added

examples/inter_canister_calls/caller.did

@@ -0,0 +1,28 @@
+type StubbornSetResult = variant {
+    Ok : null;
+    Err : text;
+};
+
+type IncrementResult = variant {
+    Ok : null;
+    Err : text;
+};
+
+type GetResult = variant {
+    Ok : nat;
+    Err : text;
+};
+
+type SignMessageResult = variant {
+    Ok : text;
+    Err : text;
+};
+
+service : {
+    call_get_and_set : ( principal, nat ) -> (nat);
+    set_then_get : (principal, nat) -> (nat);
+    call_get : (principal) -> (GetResult);
+    call_increment : (principal) -> (IncrementResult);
+    stubborn_set : (principal, nat) -> (StubbornSetResult);
+    sign_message : (text)  -> (SignMessageResult);
+}

examples/inter_canister_calls/counter.did

@@ -0,0 +1,6 @@
+service : {
+    get : () -> (nat) query;
+    set : (nat) -> ();
+    increment : () -> ();
+    get_and_set : (nat) -> (nat);
+}

examples/inter_canister_calls/inter_canister_calls_test.py

@@ -0,0 +1,90 @@
+import sys
+import os
+import unittest
+import ic
+
+# The example needs to have the module in its sys path, so we traverse
+# up until we find the pocket_ic package.
+script_dir = os.path.dirname(os.path.abspath(__file__))
+sys.path.append(os.path.dirname(os.path.dirname(script_dir)))
+
+from pocket_ic import PocketIC, SubnetConfig
+
+# This test suite is for testing inter-canister calls between a caller canister and a counter canister.
+
+# Note: The inter-canister-calls example take from https://github.com/dfinity/examples/tree/master/rust/inter-canister-calls
+
+class InterCanisterCallsTest(unittest.TestCase):
+    def setUp(self) -> None:
+        # This is run for every test individually.
+        # We create a new PocketIC with a single NNS subnet.
+        self.pic = PocketIC(SubnetConfig(nns=True))
+
+        with open(
+            os.path.join(script_dir, "caller.did"), "r", encoding="utf-8"
+        ) as candid_file:
+            candid = candid_file.read()
+
+        with open(os.path.join(script_dir, "caller.wasm"), "rb") as wasm_file:
+            wasm_module = wasm_file.read()
+
+        # Install the caller canister on the NNS subnet.
+        self.caller: ic.Canister = self.pic.create_and_install_canister_with_candid(
+            candid, bytes(wasm_module)
+        )
+
+        with open(
+            os.path.join(script_dir, "counter.did"), "r", encoding="utf-8"
+        ) as candid_file:
+            candid = candid_file.read()
+
+        with open(os.path.join(script_dir, "counter.wasm"), "rb") as wasm_file:
+            wasm_module = wasm_file.read()
+
+        # Install the counter canister on the NNS subnet.
+        self.counter: ic.Canister = self.pic.create_and_install_canister_with_candid(
+            candid, bytes(wasm_module)
+        )
+
+        return super().setUp()
+
+    def test_call_get_and_set(self):
+        # Test setting the counter to a new value and getting the old value
+        new_value = 42
+        old_value = self.caller.call_get_and_set(self.counter.canister_id.to_str(), new_value)
+        self.assertEqual(old_value, [0])  # Assuming the initial value is 0
+
+    def test_set_then_get(self):
+        # Test setting the counter and then getting the current value
+        new_value = 7
+        self.caller.set_then_get(self.counter.canister_id.to_str(), new_value)
+        current_value = self.counter.get()
+        self.assertEqual(current_value, [7])
+
+    def test_call_increment(self):
+        self.caller.set_then_get(self.counter.canister_id.to_str(), 7)
+        # Test incrementing the counter
+        self.caller.call_increment(self.counter.canister_id.to_str())
+        current_value = self.counter.get()
+        # Assuming the previous value was 7
+        self.assertEqual(current_value, [8])  
+
+    def test_call_get(self):
+        self.caller.set_then_get(self.counter.canister_id.to_str(), 7)
+        self.caller.call_increment(self.counter.canister_id.to_str())
+
+        # Test getting the current counter value
+        current_value = self.caller.call_get(self.counter.canister_id.to_str())
+        # Assuming the previous value was 8
+        self.assertEqual(current_value, [{'Ok':8}])
+
+    def test_stubborn_set(self):
+        # Test setting the counter value with retries
+        new_value = 42
+        result = self.caller.stubborn_set(self.counter.canister_id.to_str(), new_value)
+        self.assertEqual(result[0], {'Ok':None})
+        current_value = self.counter.get()
+        self.assertEqual(current_value, [42])
+
+if __name__ == "__main__":
+    unittest.main()