diff --git a/src/test/blockindex_tests.cpp b/src/test/blockindex_tests.cpp
--- a/src/test/blockindex_tests.cpp
+++ b/src/test/blockindex_tests.cpp
@@ -161,4 +161,37 @@
     }
 }
 
+BOOST_AUTO_TEST_CASE(index_isvalid) {
+    CBlockIndex index;
+
+    // Test against all validity values
+    std::set<BlockValidity> validityValues{
+        BlockValidity::UNKNOWN, BlockValidity::HEADER,
+        BlockValidity::TREE,    BlockValidity::TRANSACTIONS,
+        BlockValidity::CHAIN,   BlockValidity::SCRIPTS};
+    std::set<bool> boolValues = {false, true};
+    for (BlockValidity validity : validityValues) {
+        index.nStatus = BlockStatus().withValidity(validity);
+
+        for (bool withFailed : boolValues) {
+            index.nStatus = index.nStatus.withFailed(withFailed);
+
+            for (bool withFailedParent : boolValues) {
+                index.nStatus =
+                    index.nStatus.withFailedParent(withFailedParent);
+
+                for (BlockValidity validUpTo : validityValues) {
+                    bool isValid = index.IsValid(validUpTo);
+                    if (validUpTo <= validity && !withFailed &&
+                        !withFailedParent) {
+                        BOOST_CHECK(isValid);
+                    } else {
+                        BOOST_CHECK(!isValid);
+                    }
+                }
+            }
+        }
+    }
+}
+
 BOOST_AUTO_TEST_SUITE_END()