diff --git a/graph_utils_unittest.cc b/graph_utils_unittest.cc
index d947ddd..cfa2b5c 100644
--- a/graph_utils_unittest.cc
+++ b/graph_utils_unittest.cc
@@ -4,8 +4,11 @@
 
 #include <utility>
 #include <vector>
+
 #include <gtest/gtest.h>
+
 #include "update_engine/graph_utils.h"
+#include "update_engine/extent_ranges.h"
 
 using std::make_pair;
 using std::vector;
@@ -38,4 +41,62 @@
   EXPECT_EQ(4, graph_utils::EdgeWeight(graph, make_pair(0, 1)));
 }
 
+TEST(GraphUtilsTest, BlocksInExtentsTest) {
+  {
+    vector<Extent> extents;
+    EXPECT_EQ(0, graph_utils::BlocksInExtents(extents));
+    extents.push_back(ExtentForRange(0, 1));
+    EXPECT_EQ(1, graph_utils::BlocksInExtents(extents));
+    extents.push_back(ExtentForRange(23, 55));
+    EXPECT_EQ(56, graph_utils::BlocksInExtents(extents));
+    extents.push_back(ExtentForRange(1, 2));
+    EXPECT_EQ(58, graph_utils::BlocksInExtents(extents));
+  }
+  {
+    google::protobuf::RepeatedPtrField<Extent> extents;
+    EXPECT_EQ(0, graph_utils::BlocksInExtents(extents));
+    *extents.Add() = ExtentForRange(0, 1);
+    EXPECT_EQ(1, graph_utils::BlocksInExtents(extents));
+    *extents.Add() = ExtentForRange(23, 55);
+    EXPECT_EQ(56, graph_utils::BlocksInExtents(extents));
+    *extents.Add() = ExtentForRange(1, 2);
+    EXPECT_EQ(58, graph_utils::BlocksInExtents(extents));
+  }
+}
+
+TEST(GraphUtilsTest, DepsTest) {
+  Graph graph(3);
+  
+  graph_utils::AddReadBeforeDep(&graph[0], 1, 3);
+  EXPECT_EQ(1, graph[0].out_edges.size());
+  {
+    Extent& extent = graph[0].out_edges[1].extents[0];
+    EXPECT_EQ(3, extent.start_block());
+    EXPECT_EQ(1, extent.num_blocks());
+  }
+  graph_utils::AddReadBeforeDep(&graph[0], 1, 4);
+  EXPECT_EQ(1, graph[0].out_edges.size());
+  {
+    Extent& extent = graph[0].out_edges[1].extents[0];
+    EXPECT_EQ(3, extent.start_block());
+    EXPECT_EQ(2, extent.num_blocks());
+  }
+  graph_utils::AddReadBeforeDepExtents(&graph[2], 1,
+    vector<Extent>(1, ExtentForRange(5, 2)));
+  EXPECT_EQ(1, graph[2].out_edges.size());
+  {
+    Extent& extent = graph[2].out_edges[1].extents[0];
+    EXPECT_EQ(5, extent.start_block());
+    EXPECT_EQ(2, extent.num_blocks());
+  }
+  // Change most recent edge from read-before to write-before
+  graph[2].out_edges[1].write_extents.swap(graph[2].out_edges[1].extents);
+  graph_utils::DropWriteBeforeDeps(&graph[2].out_edges);
+  EXPECT_EQ(0, graph[2].out_edges.size());
+  
+  EXPECT_EQ(1, graph[0].out_edges.size());
+  graph_utils::DropIncomingEdgesTo(&graph, 1);
+  EXPECT_EQ(0, graph[0].out_edges.size());
+}
+
 }  // namespace chromeos_update_engine