diff --git a/test/phase/BUILD b/test/phase/BUILD
new file mode 100644
index 0000000000..f842eef4c8
--- /dev/null
+++ b/test/phase/BUILD
@@ -0,0 +1,22 @@
+load(
+    "//test/phase:customizability_test.bzl",
+    "add_phase_customizability_test_singleton",
+    "customizability_test_scala_binary",
+    "customizability_test_scala_library",
+)
+
+add_phase_customizability_test_singleton(
+    name = "phase_customizability_test",
+    visibility = ["//visibility:public"],
+)
+
+customizability_test_scala_binary(
+    name = "HelloBinary",
+    srcs = ["HelloBinary.scala"],
+    main_class = "scalarules.test.phase.HelloBinary",
+)
+
+customizability_test_scala_library(
+    name = "HelloLibrary",
+    srcs = ["HelloLibrary.scala"],
+)
diff --git a/test/phase/HelloBinary.scala b/test/phase/HelloBinary.scala
new file mode 100644
index 0000000000..3bc83a23e2
--- /dev/null
+++ b/test/phase/HelloBinary.scala
@@ -0,0 +1,7 @@
+package scalarules.test.phase
+
+object HelloBinary {
+  def main(args: Array[String]) {
+    println("You can customize binary phases!")
+  }
+}
diff --git a/test/phase/HelloLibrary.scala b/test/phase/HelloLibrary.scala
new file mode 100644
index 0000000000..8b3855fe5c
--- /dev/null
+++ b/test/phase/HelloLibrary.scala
@@ -0,0 +1,5 @@
+package scalarules.test.phase
+
+object HelloLibrary {
+  println("You can customize library phases!")
+}
diff --git a/test/phase/customizability_test.bzl b/test/phase/customizability_test.bzl
new file mode 100644
index 0000000000..afd1b35830
--- /dev/null
+++ b/test/phase/customizability_test.bzl
@@ -0,0 +1,35 @@
+load(
+    "//scala:providers.bzl",
+    _ScalaRulePhase = "ScalaRulePhase",
+)
+load(
+    "//test/phase:phase_customizability_test.bzl",
+    _phase_customizability_test = "phase_customizability_test",
+)
+load(
+    "//scala:scala.bzl",
+    _make_scala_binary = "make_scala_binary",
+    _make_scala_library = "make_scala_library",
+)
+
+ext_add_phase_customizability_test = {
+    "phase_providers": [
+        "//test/phase:phase_customizability_test",
+    ],
+}
+
+def _add_phase_customizability_test_singleton_implementation(ctx):
+    return [
+        _ScalaRulePhase(
+            phases = [
+                ("-", "coda", "customizability_test", _phase_customizability_test),
+            ],
+        ),
+    ]
+
+add_phase_customizability_test_singleton = rule(
+    implementation = _add_phase_customizability_test_singleton_implementation,
+)
+
+customizability_test_scala_binary = _make_scala_binary(ext_add_phase_customizability_test)
+customizability_test_scala_library = _make_scala_library(ext_add_phase_customizability_test)
diff --git a/test/phase/phase_customizability_test.bzl b/test/phase/phase_customizability_test.bzl
new file mode 100644
index 0000000000..ee95c10622
--- /dev/null
+++ b/test/phase/phase_customizability_test.bzl
@@ -0,0 +1,7 @@
+#
+# PHASE: customizability test
+#
+# A dummy test phase to make sure rules are customizable
+#
+def phase_customizability_test(ctx, p):
+    print("customizable phase")
diff --git a/test/shell/test_helper.sh b/test/shell/test_helper.sh
index 7e5f1b9891..99e42eb1b2 100755
--- a/test/shell/test_helper.sh
+++ b/test/shell/test_helper.sh
@@ -60,6 +60,25 @@ action_should_fail_with_message() {
   fi
 }
 
+action_should_contain_message() {
+  set +e
+  MSG=$1
+  TEST_ARG=${@:2}
+  RES=$(bazel $TEST_ARG 2>&1)
+  RESPONSE_CODE=$?
+  echo $RES | grep -- "$MSG"
+  GREP_RES=$?
+  if [ $RESPONSE_CODE -ne 0 ]; then
+    echo -e "${RED} \"bazel $TEST_ARG\" should pass but failed. $NC"
+    exit 1
+  elif [ $GREP_RES -ne 0 ]; then
+    echo -e "${RED} \"bazel $TEST_ARG\" should pass with message \"$MSG\" but did not. $NC"
+    exit 1
+  else
+    exit 0
+  fi
+}
+
 test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message() {
   set +e
 
diff --git a/test/shell/test_phase.sh b/test/shell/test_phase.sh
new file mode 100755
index 0000000000..016fdf060a
--- /dev/null
+++ b/test/shell/test_phase.sh
@@ -0,0 +1,20 @@
+# shellcheck source=./test_runner.sh
+dir=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+. "${dir}"/test_runner.sh
+. "${dir}"/test_helper.sh
+runner=$(get_test_runner "${1:-local}")
+
+test_binary_with_extra_phase() {
+  action_should_contain_message \
+    "customizable phase" \
+    build //test/phase:HelloBinary
+}
+
+test_library_with_extra_phase() {
+  action_should_contain_message \
+    "customizable phase" \
+    build //test/phase:HelloLibrary
+}
+
+$runner test_binary_with_extra_phase
+$runner test_library_with_extra_phase
diff --git a/test_rules_scala.sh b/test_rules_scala.sh
index 04b1ced740..e8456fabfe 100755
--- a/test_rules_scala.sh
+++ b/test_rules_scala.sh
@@ -29,6 +29,7 @@ $runner bazel test //test/... --extra_toolchains="//test_expect_failure/plus_one
 . "${test_dir}"/test_javac_jvm_flags.sh
 . "${test_dir}"/test_junit.sh
 . "${test_dir}"/test_misc.sh
+. "${test_dir}"/test_phase.sh
 . "${test_dir}"/test_scala_binary.sh
 . "${test_dir}"/test_scalac_jvm_flags.sh
 . "${test_dir}"/test_scala_classpath.sh