diff --git a/beacon_node/beacon_chain/test_harness/examples/chain.yaml b/beacon_node/beacon_chain/test_harness/examples/chain.yaml
index 5d8e34795..b170a0b2e 100644
--- a/beacon_node/beacon_chain/test_harness/examples/chain.yaml
+++ b/beacon_node/beacon_chain/test_harness/examples/chain.yaml
@@ -8,6 +8,7 @@ test_cases:
       epoch_length: 64
       deposits_for_chain_start: 1000
       num_slots: 32 # Testing advancing state to slot < SlotsPerEpoch
+      skip_slots: [2, 3]
     results:
       slot: 32
       num_validators: 1000
diff --git a/beacon_node/beacon_chain/test_harness/src/bin.rs b/beacon_node/beacon_chain/test_harness/src/bin.rs
index 007ec3f60..48f349d4a 100644
--- a/beacon_node/beacon_chain/test_harness/src/bin.rs
+++ b/beacon_node/beacon_chain/test_harness/src/bin.rs
@@ -1,8 +1,10 @@
 use self::beacon_chain_harness::BeaconChainHarness;
 use self::validator_harness::ValidatorHarness;
+use beacon_chain::CheckPoint;
 use clap::{App, Arg};
 use env_logger::{Builder, Env};
-use log::info;
+use log::{info, warn};
+use std::collections::HashMap;
 use std::{fs::File, io::prelude::*};
 use types::*;
 use yaml_rust::{Yaml, YamlLoader};
@@ -39,7 +41,7 @@ fn main() {
         for doc in &docs {
             for test_case in doc["test_cases"].as_vec().unwrap() {
                 let manifest = Manifest::from_yaml(test_case);
-                manifest.execute();
+                manifest.assert_result_valid(manifest.execute())
             }
         }
     }
@@ -68,7 +70,7 @@ impl Manifest {
         spec
     }
 
-    pub fn execute(&self) {
+    pub fn execute(&self) -> ExecutionResult {
         let spec = self.spec();
         let validator_count = self.config.deposits_for_chain_start;
         let slots = self.results.slot;
@@ -82,18 +84,47 @@ impl Manifest {
 
         info!("Starting simulation across {} slots...", slots);
 
-        for _ in 0..self.results.slot {
-            harness.advance_chain_with_block();
+        for slot_height in 0..self.results.slot {
+            match self.config.skip_slots {
+                Some(ref skip_slots) if skip_slots.contains(&slot_height) => {
+                    warn!("Skipping slot at height {}.", slot_height);
+                    harness.increment_beacon_chain_slot();
+                }
+                _ => {
+                    info!("Producing block at slot height {}.", slot_height);
+                    harness.advance_chain_with_block();
+                }
+            }
         }
 
         harness.run_fork_choice();
 
-        let dump = harness.chain_dump().expect("Chain dump failed.");
+        info!("Test execution complete!");
 
-        assert_eq!(dump.len() as u64, slots + 1); // + 1 for genesis block.
-
-        // harness.dump_to_file("/tmp/chaindump.json".to_string(), &dump);
+        ExecutionResult {
+            chain: harness.chain_dump().expect("Chain dump failed."),
+        }
     }
+
+    pub fn assert_result_valid(&self, result: ExecutionResult) {
+        info!("Verifying test results...");
+
+        if let Some(ref skip_slots) = self.config.skip_slots {
+            for checkpoint in result.chain {
+                let block_slot = checkpoint.beacon_block.slot.as_u64();
+                assert!(
+                    !skip_slots.contains(&block_slot),
+                    "Slot {} was not skipped.",
+                    block_slot
+                );
+            }
+        }
+        info!("OK: Skipped slots not present in chain.");
+    }
+}
+
+struct ExecutionResult {
+    pub chain: Vec<CheckPoint>,
 }
 
 struct Results {
@@ -117,6 +148,7 @@ impl Results {
 struct Config {
     pub deposits_for_chain_start: usize,
     pub epoch_length: Option<u64>,
+    pub skip_slots: Option<Vec<u64>>,
 }
 
 impl Config {
@@ -125,6 +157,7 @@ impl Config {
             deposits_for_chain_start: as_usize(&yaml, "deposits_for_chain_start")
                 .expect("Must specify validator count"),
             epoch_length: as_u64(&yaml, "epoch_length"),
+            skip_slots: as_vec_u64(yaml, "skip_slots"),
         }
     }
 }