diff --git a/ui/build/test_build.go b/ui/build/test_build.go
new file mode 100644
index 0000000..940f0c8
--- /dev/null
+++ b/ui/build/test_build.go
@@ -0,0 +1,85 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package build
+
+import (
+	"bufio"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// Checks for files in the out directory that have a rule that depends on them but no rule to
+// create them. This catches a common set of build failures where a rule to generate a file is
+// deleted (either by deleting a module in an Android.mk file, or by modifying the build system
+// incorrectly).  These failures are often not caught by a local incremental build because the
+// previously built files are still present in the output directory.
+func testForDanglingRules(ctx Context, config Config) {
+	// Many modules are disabled on mac.  Checking for dangling rules would cause lots of build
+	// breakages, and presubmit wouldn't catch them, so just disable the check.
+	if runtime.GOOS != "linux" {
+		return
+	}
+
+	ctx.BeginTrace("test for dangling rules")
+	defer ctx.EndTrace()
+
+	// Get a list of leaf nodes in the dependency graph from ninja
+	executable := config.PrebuiltBuildTool("ninja")
+
+	args := []string{}
+	args = append(args, config.NinjaArgs()...)
+	args = append(args, "-f", config.CombinedNinjaFile())
+	args = append(args, "-t", "targets", "rule")
+
+	cmd := Command(ctx, config, "ninja", executable, args...)
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		ctx.Fatal(err)
+	}
+
+	cmd.StartOrFatal()
+
+	outDir := config.OutDir()
+	bootstrapDir := filepath.Join(outDir, "soong", ".bootstrap")
+	miniBootstrapDir := filepath.Join(outDir, "soong", ".minibootstrap")
+
+	var danglingRules []string
+
+	scanner := bufio.NewScanner(stdout)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.HasPrefix(line, outDir) {
+			// Leaf node is not in the out directory.
+			continue
+		}
+		if strings.HasPrefix(line, bootstrapDir) || strings.HasPrefix(line, miniBootstrapDir) {
+			// Leaf node is in one of Soong's bootstrap directories, which do not have
+			// full build rules in the primary build.ninja file.
+			continue
+		}
+		danglingRules = append(danglingRules, line)
+	}
+
+	cmd.WaitOrFatal()
+
+	if len(danglingRules) > 0 {
+		ctx.Println("Dependencies in out found with no rule to create them:")
+		for _, dep := range danglingRules {
+			ctx.Println(dep)
+		}
+		ctx.Fatal("")
+	}
+}