Better error messages for DryRunInspector.from_single_response()

CHANGELOG.md

@@ -1,6 +1,12 @@
 <!-- markdownlint-disable MD024 -->
 # Changelog
 
+## `v0.1.2`
+
+### Fixed
+
+* Misleading error message in the case of an erroring dry run response
+
 ## `v0.1.1`
 
 ### Added

graviton/blackbox.py

@@ -449,6 +449,9 @@ def get_txn_mode(cls, txn: dict) -> ExecutionMode:
 
     @classmethod
     def from_single_response(cls, dryrun_resp: dict) -> "DryRunInspector":
+        error = dryrun_resp.get("error")
+        assert not error, f"dryrun response included the following error: [{error}]"
+
         txns = dryrun_resp.get("txns") or []
         assert (
             len(txns) == 1

tests/unit/inspector_test.py

@@ -0,0 +1,70 @@
+import pytest
+
+from graviton.blackbox import DryRunInspector
+
+
+def test_from_single_response_errors():
+    error_resp = {
+        "error": "dryrun Source[0]: 1 error",
+        "protocol-version": "future",
+        "txns": None,
+    }
+
+    with pytest.raises(AssertionError) as ae:
+        DryRunInspector.from_single_response(error_resp)
+
+    assert (
+        ae.value.args[0]
+        == "dryrun response included the following error: [dryrun Source[0]: 1 error]"
+    )
+
+    no_txns_resp1 = {
+        "error": None,
+        "protocol-version": "future",
+        "txns": None,
+    }
+
+    with pytest.raises(AssertionError) as ae:
+        DryRunInspector.from_single_response(no_txns_resp1)
+
+    assert (
+        ae.value.args[0]
+        == "require exactly 1 dry run transaction to create a singleton but had 0 instead"
+    )
+
+    no_txns_resp2 = {
+        "protocol-version": "future",
+        "txns": None,
+    }
+
+    with pytest.raises(AssertionError) as ae:
+        DryRunInspector.from_single_response(no_txns_resp2)
+
+    assert (
+        ae.value.args[0]
+        == "require exactly 1 dry run transaction to create a singleton but had 0 instead"
+    )
+
+    too_many_txns_resp = {"protocol-version": "future", "txns": [1, 2, 3]}
+
+    with pytest.raises(AssertionError) as ae:
+        DryRunInspector.from_single_response(too_many_txns_resp)
+
+    assert (
+        ae.value.args[0]
+        == "require exactly 1 dry run transaction to create a singleton but had 3 instead"
+    )
+
+    too_many_txns_resp_w_err = {
+        "error": "this is REALLLY REALLY BAD!!!",
+        "protocol-version": "future",
+        "txns": [1, 2, 3],
+    }
+
+    with pytest.raises(AssertionError) as ae:
+        DryRunInspector.from_single_response(too_many_txns_resp_w_err)
+
+    assert (
+        ae.value.args[0]
+        == "dryrun response included the following error: [this is REALLLY REALLY BAD!!!]"
+    )