diff --git a/src/branch.ts b/src/branch.ts
new file mode 100644
index 00000000..e2637896
--- /dev/null
+++ b/src/branch.ts
@@ -0,0 +1,42 @@
+import * as core from '@actions/core';
+import * as github from '@actions/github';
+
+function getHeadBranchName(): string | undefined {
+  const pullRequest = github.context.payload.pull_request;
+  if (!pullRequest) {
+    return undefined;
+  }
+
+  return pullRequest.head?.ref;
+}
+
+export function checkBranch(glob: string[]): boolean {
+  const branchName = getHeadBranchName();
+  if (!branchName) {
+    core.debug(` no branch name`);
+    return false;
+  }
+
+  core.debug(` checking "branch" pattern against ${branchName}`);
+  const matchers = glob.map(g => new RegExp(g));
+  for (const matcher of matchers) {
+    if (matchBranchPattern(matcher, branchName)) {
+      core.debug(`  "branch" patterns matched against ${branchName}`);
+      return true;
+    }
+  }
+
+  core.debug(`  "branch" patterns did not match against ${branchName}`);
+  return false;
+}
+
+function matchBranchPattern(matcher: RegExp, branchName: string): boolean {
+  core.debug(`  - ${matcher}`);
+  if (matcher.test(branchName)) {
+    core.debug(`   "branch" pattern matched`);
+    return true;
+  }
+
+  core.debug(`   ${matcher} did not match`);
+  return false;
+}
diff --git a/src/labeler.ts b/src/labeler.ts
index 9b3c31b3..75bcb4c4 100644
--- a/src/labeler.ts
+++ b/src/labeler.ts
@@ -3,6 +3,8 @@ import * as github from '@actions/github';
 import * as yaml from 'js-yaml';
 import {Minimatch, IMinimatch} from 'minimatch';
 
+import {checkBranch} from './branch';
+
 interface MatchConfig {
   all?: string[];
   any?: string[];
@@ -72,15 +74,6 @@ function getPrNumber(): number | undefined {
   return pullRequest.number;
 }
 
-function getHeadBranchName(): string | undefined {
-  const pullRequest = github.context.payload.pull_request;
-  if (!pullRequest) {
-    return undefined;
-  }
-
-  return pullRequest.head?.ref;
-}
-
 async function getChangedFiles(
   client: ClientType,
   prNumber: number
@@ -228,37 +221,6 @@ function checkAll(changedFiles: string[], globs: string[]): boolean {
   return true;
 }
 
-function matchBranchPattern(matcher: RegExp, branchName: string): boolean {
-  core.debug(`  - ${matcher}`);
-  if (matcher.test(branchName)) {
-    core.debug(`   "branch" pattern matched`);
-    return true;
-  }
-
-  core.debug(`   ${matcher} did not match`);
-  return false;
-}
-
-function checkBranch(glob: string[]): boolean {
-  const branchName = getHeadBranchName();
-  if (!branchName) {
-    core.debug(` no branch name`);
-    return false;
-  }
-
-  core.debug(` checking "branch" pattern against ${branchName}`);
-  const matchers = glob.map(g => new RegExp(g));
-  for (const matcher of matchers) {
-    if (matchBranchPattern(matcher, branchName)) {
-      core.debug(`  "branch" patterns matched against ${branchName}`);
-      return true;
-    }
-  }
-
-  core.debug(`  "branch" patterns did not match against ${branchName}`);
-  return false;
-}
-
 function checkMatch(changedFiles: string[], matchConfig: MatchConfig): boolean {
   if (matchConfig.all !== undefined) {
     if (!checkAll(changedFiles, matchConfig.all)) {