More tests

src/tests/libxrpl/tx/wasm/host_context/LedgerObjNestedArrayLen.cpp

@@ -0,0 +1,97 @@
+#include <xrpl/tx/wasm/WasmCommon.h>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <tx/wasm/HostContextFixture.h>
+
+#include <cstdint>
+#include <expected>
+#include <stdexcept>
+#include <vector>
+
+namespace xrpl::test {
+
+// The engine's own rules - buffer-fit, the field cap, guest memory - are tested on the Rust
+// side, not here.
+//
+// No out region and no axis E: `getLedgerObjNestedArrayLen` answers the array's element
+// count directly rather than through a written buffer.
+struct LedgerObjNestedArrayLenCall : HostContextTest
+{
+    std::int32_t const cacheIdx = 7;
+    std::vector<std::int32_t> const steps{5, -12, 130};
+    Bytes const locatorBytes = bytesOfSteps(steps);
+};
+
+TEST_F(LedgerObjNestedArrayLenCall, LocatorBytesBecomeFieldLocatorHostReturnsCount)
+{
+    EXPECT_CALL(host, getLedgerObjNestedArrayLen(cacheIdx, LocatorEquals(steps)))
+        .WillOnce(testing::Return(7));
+
+    EXPECT_EQ(hostContext.getLedgerObjNestedArrayLen(cacheIdx, bytesOf(locatorBytes)), 7);
+}
+
+// `NoArray` - the field the locator resolves to is not an array - is the error this shape
+// most plausibly returns, so it stands in for axis B.
+TEST_F(LedgerObjNestedArrayLenCall, HostErrorBecomesContractReturnValue)
+{
+    EXPECT_CALL(host, getLedgerObjNestedArrayLen(cacheIdx, LocatorEquals(steps)))
+        .WillOnce(testing::Return(std::unexpected(HostFunctionError::NoArray)));
+
+    EXPECT_EQ(
+        hostContext.getLedgerObjNestedArrayLen(cacheIdx, bytesOf(locatorBytes)),
+        hfErrorToInt(HostFunctionError::NoArray));
+}
+
+TEST_F(LedgerObjNestedArrayLenCall, EmptyLocatorIsRefusedWithoutAskingHost)
+{
+    EXPECT_CALL(host, getLedgerObjNestedArrayLen).Times(0);
+
+    EXPECT_EQ(
+        hostContext.getLedgerObjNestedArrayLen(cacheIdx, bytesOf(Bytes{})),
+        hfErrorToInt(HostFunctionError::LocatorMalformed));
+}
+
+// Distinct from an empty locator: `invokeWithLocator` checks the two conditions separately.
+TEST_F(LedgerObjNestedArrayLenCall, MisalignedLocatorLengthIsRefusedWithoutAskingHost)
+{
+    Bytes const oddLength{1, 2, 3};
+    EXPECT_CALL(host, getLedgerObjNestedArrayLen).Times(0);
+
+    EXPECT_EQ(
+        hostContext.getLedgerObjNestedArrayLen(cacheIdx, bytesOf(oddLength)),
+        hfErrorToInt(HostFunctionError::LocatorMalformed));
+}
+
+TEST_F(LedgerObjNestedArrayLenCall, HostExceptionBecomesInternalFatalAndIsLogged)
+{
+    EXPECT_CALL(host, getLedgerObjNestedArrayLen(cacheIdx, LocatorEquals(steps)))
+        .WillOnce(testing::Throw(std::runtime_error{"ledger obj nested array len came apart"}));
+
+    EXPECT_EQ(
+        hostContext.getLedgerObjNestedArrayLen(cacheIdx, bytesOf(locatorBytes)),
+        hfErrorToInt(HostFunctionError::InternalFatal));
+    EXPECT_THAT(logged(), testing::HasSubstr("ledger obj nested array len came apart"));
+    EXPECT_THAT(logged(), testing::HasSubstr("getLedgerObjNestedArrayLen"));
+}
+
+// `cacheIdx` crosses to the host as its own `std::int32_t`, unlike a keylet method's `seq`:
+// no cast to an unsigned bit pattern, so 0 and a negative slot both cross unchanged.
+TEST_F(LedgerObjNestedArrayLenCall, ZeroCacheIdxArrivesAtHostUnchanged)
+{
+    EXPECT_CALL(host, getLedgerObjNestedArrayLen(0, LocatorEquals(steps)))
+        .WillOnce(testing::Return(7));
+
+    EXPECT_EQ(hostContext.getLedgerObjNestedArrayLen(0, bytesOf(locatorBytes)), 7);
+}
+
+TEST_F(LedgerObjNestedArrayLenCall, NegativeCacheIdxArrivesAtHostUnchanged)
+{
+    std::int32_t const negativeCacheIdx = -3;
+    EXPECT_CALL(host, getLedgerObjNestedArrayLen(negativeCacheIdx, LocatorEquals(steps)))
+        .WillOnce(testing::Return(7));
+
+    EXPECT_EQ(hostContext.getLedgerObjNestedArrayLen(negativeCacheIdx, bytesOf(locatorBytes)), 7);
+}
+
+}  // namespace xrpl::test