diff --git a/chain-test/src/test/scala/org/bitcoins/chain/blockchain/BlockchainTest.scala b/chain-test/src/test/scala/org/bitcoins/chain/blockchain/BlockchainTest.scala
index 8d114f81eb..ca94bdfe73 100644
--- a/chain-test/src/test/scala/org/bitcoins/chain/blockchain/BlockchainTest.scala
+++ b/chain-test/src/test/scala/org/bitcoins/chain/blockchain/BlockchainTest.scala
@@ -21,6 +21,17 @@ class BlockchainTest extends ChainUnitTest {
 
   behavior of "Blockchain"
 
+  it must "have the correct toString" inFixtured {
+    case ChainFixture.Empty =>
+      val genesis = ChainUnitTest.genesisHeaderDb
+      val headerDb =
+        BlockHeaderHelper.buildNextHeader(genesis)
+      val chain = Blockchain(Vector(headerDb, genesis))
+
+      assert(
+        chain.toString == s"BaseBlockchain(tip=$headerDb,last=$genesis,length=2)")
+  }
+
   it must "connect a new header to the current tip of a blockchain" inFixtured {
     case ChainFixture.Empty =>
       val blockchain = Blockchain.fromHeaders(
diff --git a/chain-test/src/test/scala/org/bitcoins/chain/blockchain/ChainHandlerTest.scala b/chain-test/src/test/scala/org/bitcoins/chain/blockchain/ChainHandlerTest.scala
index 5780e70dfe..ae273bafdc 100644
--- a/chain-test/src/test/scala/org/bitcoins/chain/blockchain/ChainHandlerTest.scala
+++ b/chain-test/src/test/scala/org/bitcoins/chain/blockchain/ChainHandlerTest.scala
@@ -3,6 +3,7 @@ package org.bitcoins.chain.blockchain
 import org.bitcoins.chain.{ChainCallbacks, OnBlockHeaderConnected}
 import org.bitcoins.chain.pow.Pow
 import org.bitcoins.core.api.chain.ChainApi
+import org.bitcoins.core.api.chain.ChainQueryApi.FilterResponse
 import org.bitcoins.core.api.chain.db.{BlockHeaderDb, BlockHeaderDbHelper}
 import org.bitcoins.core.gcs.{BlockFilter, FilterHeader}
 import org.bitcoins.core.number.{Int32, UInt32}
@@ -519,14 +520,40 @@ class ChainHandlerTest extends ChainDbUnitTest {
       bestBlock <- chainHandler.getBestBlockHeader()
       stamp1 = BlockStamp.BlockHash(bestBlock.hashBE)
       stamp2 = BlockStamp.BlockHeight(bestBlock.height)
-      stamp3 = BlockStamp.BlockTime(bestBlock.time)
       height1 <- chainHandler.getHeightByBlockStamp(stamp1)
       height2 <- chainHandler.getHeightByBlockStamp(stamp2)
-      // TODO implement BlockTime
-//      height3 <- chainHandler.getHeightByBlockStamp(stamp3)
     } yield {
       assert(height1 == height2)
-//      assert(height1 == height3)
+    }
+  }
+
+  it must "fail to return the height by block time" in {
+    chainHandler: ChainHandler =>
+      recoverToSucceededIf[RuntimeException] {
+        for {
+          bestBlock <- chainHandler.getBestBlockHeader()
+          stamp = BlockStamp.BlockTime(bestBlock.time)
+          height <- chainHandler.getHeightByBlockStamp(stamp)
+        } yield height
+      }
+  }
+
+  it must "fail to return the height by block stamp with an unknown hash" in {
+    chainHandler: ChainHandler =>
+      recoverToSucceededIf[UnknownBlockHash] {
+        val stamp = BlockStamp.BlockHash(DoubleSha256DigestBE.empty)
+        chainHandler.getHeightByBlockStamp(stamp)
+      }
+  }
+
+  it must "find filters between heights" in { chainHandler: ChainHandler =>
+    chainHandler.getFiltersBetweenHeights(0, 1).map { filters =>
+      val genesis = ChainUnitTest.genesisFilterDb
+      val genesisFilterResponse = FilterResponse(genesis.golombFilter,
+                                                 genesis.blockHashBE,
+                                                 genesis.height)
+
+      assert(filters == Vector(genesisFilterResponse))
     }
   }
 
@@ -567,6 +594,27 @@ class ChainHandlerTest extends ChainDbUnitTest {
     }
   }
 
+  it must "check isMissingChainWork when there is over a 100 headers" in {
+    chainHandler: ChainHandler =>
+      val genesis = ChainUnitTest.genesisHeaderDb
+      val headers = 0.to(101).foldLeft(Vector(genesis)) { (accum, _) =>
+        val next = BlockHeaderHelper.buildNextHeader(accum.last)
+        accum :+ next
+      }
+
+      val noWork = BlockHeaderHelper
+        .buildNextHeader(headers.last)
+        .copy(chainWork = BigInt(0))
+
+      for {
+        _ <- chainHandler.blockHeaderDAO.upsertAll(headers)
+        isMissingFirst100 <- chainHandler.isMissingChainWork
+        _ = assert(!isMissingFirst100)
+        _ <- chainHandler.blockHeaderDAO.create(noWork)
+        isMissingLast100 <- chainHandler.isMissingChainWork
+      } yield assert(isMissingLast100)
+  }
+
   it must "process a new valid block header with a callback" in {
     chainHandler: ChainHandler =>
       val resultP: Promise[Boolean] = Promise()
@@ -578,7 +626,7 @@ class ChainHandlerTest extends ChainDbUnitTest {
         }
       }
 
-      val callbacks = ChainCallbacks(Vector(callback))
+      val callbacks = ChainCallbacks.onBlockHeaderConnected(callback)
       chainHandler.chainConfig.addCallbacks(callbacks)
 
       val newValidHeader =
diff --git a/chain-test/src/test/scala/org/bitcoins/chain/blockchain/MainnetChainHandlerTest.scala b/chain-test/src/test/scala/org/bitcoins/chain/blockchain/MainnetChainHandlerTest.scala
index 49ab42009d..0857f98a40 100644
--- a/chain-test/src/test/scala/org/bitcoins/chain/blockchain/MainnetChainHandlerTest.scala
+++ b/chain-test/src/test/scala/org/bitcoins/chain/blockchain/MainnetChainHandlerTest.scala
@@ -190,13 +190,18 @@ class MainnetChainHandlerTest extends ChainDbUnitTest {
                                           ChainTestUtil.blockHeader562462)
     )
 
+    val noWorkGenesis = genesis.copy(chainWork = BigInt(0))
+
     val blockchain =
-      Blockchain(headersWithNoWork :+ genesis.copy(chainWork = BigInt(0)))
+      Blockchain(headersWithNoWork :+ noWorkGenesis)
 
     val chainHandler = tempHandler.copy(blockchains = Vector(blockchain))
 
     for {
+      _ <- chainHandler.blockHeaderDAO.update(noWorkGenesis)
       _ <- chainHandler.blockHeaderDAO.createAll(headersWithNoWork)
+      lowestNoWork <- chainHandler.blockHeaderDAO.getLowestNoWorkHeight
+      _ = assert(lowestNoWork == 0)
       isMissingWork <- chainHandler.isMissingChainWork
       _ = assert(isMissingWork)
       newHandler <- chainHandler.recalculateChainWork
diff --git a/chain/src/main/scala/org/bitcoins/chain/ChainCallbacks.scala b/chain/src/main/scala/org/bitcoins/chain/ChainCallbacks.scala
index 831305a56c..96b8272bbc 100644
--- a/chain/src/main/scala/org/bitcoins/chain/ChainCallbacks.scala
+++ b/chain/src/main/scala/org/bitcoins/chain/ChainCallbacks.scala
@@ -37,12 +37,12 @@ object ChainCallbacks {
     override def +(other: ChainCallbacks): ChainCallbacks =
       copy(onBlockHeaderConnected =
         onBlockHeaderConnected ++ other.onBlockHeaderConnected)
-
-    /** Constructs a set of callbacks that only acts on block headers connected */
-    def onBlockHeaderConnected(f: OnBlockHeaderConnected): ChainCallbacks =
-      ChainCallbacks(onBlockHeaderConnected = Vector(f))
   }
 
+  /** Constructs a set of callbacks that only acts on block headers connected */
+  def onBlockHeaderConnected(f: OnBlockHeaderConnected): ChainCallbacks =
+    ChainCallbacks(onBlockHeaderConnected = Vector(f))
+
   lazy val empty: ChainCallbacks =
     ChainCallbacks(onBlockHeaderConnected = Vector.empty)