diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index a32837d..32cb299 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -3,6 +3,32 @@ name: Testing
 on: [push, pull_request]
 
 jobs:
+  test:
+    name: Run tests
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+
+      - name: Install codespell
+        run: pip3 --quiet --quiet install codespell
+
+      - name: Install Bats
+        run: |
+          git clone --quiet https://github.com/bats-core/bats-core.git
+          cd bats-core
+          git fetch --tags
+          # Checkout the latest tag
+          git checkout --quiet $(git describe --tags `git rev-list --tags --max-count=1`)
+          sudo ./install.sh "/usr/local" > /dev/null
+
+      - name: Run Bats tests
+        run: bats "./test"
+
   run_action:
     name: Test run action
     runs-on: ubuntu-latest
@@ -10,5 +36,5 @@ jobs:
     - uses: actions/checkout@v1
     - uses: ./
       with:
-        path: example
+        path: test/testdata
         only_warn: 1
diff --git a/entrypoint.sh b/entrypoint.sh
index 7c486e0..203cace 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -33,8 +33,9 @@ else
     echo "Codespell found one or more problems"
 fi
 
-# Remove the matcher, so no other jobs hit it.
-echo "::remove-matcher owner=codespell::"
+# Remove the matchers, so no other jobs hit them.
+echo "::remove-matcher owner=codespell-matcher-default::"
+echo "::remove-matcher owner=codespell-matcher-specified::"
 
 # If we are in warn-only mode, return always as if we pass
 if [ -n "${INPUT_ONLY_WARN}" ]; then
diff --git a/test/exclude-file.txt b/test/exclude-file.txt
new file mode 100644
index 0000000..795e9e7
--- /dev/null
+++ b/test/exclude-file.txt
@@ -0,0 +1,2 @@
+1 abandonned 1
+2 abandonned 2
diff --git a/test/test.bats b/test/test.bats
new file mode 100644
index 0000000..ea6b853
--- /dev/null
+++ b/test/test.bats
@@ -0,0 +1,84 @@
+#!/usr/bin/env bats
+
+# Tests using the Bats testing framework
+# https://github.com/bats-core/bats-core
+
+ROOT_MISSPELLING_COUNT=5
+FILENAME_MISSPELLING_COUNT=1
+HIDDEN_MISSPELLING_COUNT=1
+EXCLUDED_MISSPELLING_COUNT=1
+SUBFOLDER_MISSPELLING_COUNT=1
+
+export RUNNER_TEMP="/foo/runner_temp"
+
+# This function runs before every test
+function setup() {
+    # Set default input values
+    export INPUT_CHECK_FILENAMES=""
+    export INPUT_CHECK_HIDDEN=""
+    export INPUT_EXCLUDE_FILE=""
+    export INPUT_PATH="./test/testdata"
+    export INPUT_ONLY_WARN=""
+}
+
+@test "Run with defaults" {
+    # codespell's exit status is the number of misspelled words found
+    expectedExitStatus=$((ROOT_MISSPELLING_COUNT + HIDDEN_MISSPELLING_COUNT + SUBFOLDER_MISSPELLING_COUNT))
+    run "./entrypoint.sh"
+    [ $status -eq $expectedExitStatus ]
+
+    # Check output
+    [ "${lines[1]}" == "::add-matcher::${RUNNER_TEMP}/_github_workflow/codespell-matcher.json" ]
+    outputRegex="^Running codespell on '${INPUT_PATH}'"
+    [[ "${lines[2]}" =~ $outputRegex ]]
+    [ "${lines[-3]}" == "Codespell found one or more problems" ]
+    [ "${lines[-2]}" == "::remove-matcher owner=codespell-matcher-default::" ]
+    [ "${lines[-1]}" == "::remove-matcher owner=codespell-matcher-specified::" ]
+}
+
+@test "Check file names" {
+    expectedExitStatus=$((ROOT_MISSPELLING_COUNT + HIDDEN_MISSPELLING_COUNT + SUBFOLDER_MISSPELLING_COUNT + FILENAME_MISSPELLING_COUNT))
+    INPUT_CHECK_FILENAMES=true
+    run "./entrypoint.sh"
+    [ $status -eq $expectedExitStatus ]
+}
+
+@test "Check a hidden file" {
+    # codespell --check-hidden has a somewhat unintuitive behavior. When run on
+    # a directory, codespell works on hidden files even if this option is not
+    # enabled. It's only when INPUT_PATH points directly at a hidden file that
+    # codespell ignores it by default.
+    expectedExitStatus=$HIDDEN_MISSPELLING_COUNT
+    INPUT_CHECK_HIDDEN=true
+    INPUT_PATH="./test/testdata/.hidden"
+    run "./entrypoint.sh"
+    [ $status -eq $expectedExitStatus ]
+}
+
+@test "Check a hidden file without INPUT_CHECK_HIDDEN set" {
+    expectedExitStatus=0
+    INPUT_PATH="./test/testdata/.hidden"
+    run "./entrypoint.sh"
+    [ $status -eq $expectedExitStatus ]
+}
+
+@test "Use an exclude file" {
+    expectedExitStatus=$((ROOT_MISSPELLING_COUNT + HIDDEN_MISSPELLING_COUNT + SUBFOLDER_MISSPELLING_COUNT - EXCLUDED_MISSPELLING_COUNT))
+    INPUT_EXCLUDE_FILE="./test/exclude-file.txt"
+    run "./entrypoint.sh"
+    [ $status -eq $expectedExitStatus ]
+}
+
+@test "Custom path" {
+    expectedExitStatus=$((SUBFOLDER_MISSPELLING_COUNT))
+    INPUT_PATH="./test/testdata/subfolder"
+    run "./entrypoint.sh"
+    [ $status -eq $expectedExitStatus ]
+}
+
+@test "Only warn" {
+    expectedExitStatus=0
+    INPUT_ONLY_WARN=true
+    run "./entrypoint.sh"
+    [ $status -eq $expectedExitStatus ]
+}
diff --git a/test/testdata/.hidden b/test/testdata/.hidden
new file mode 100644
index 0000000..3eda6e1
--- /dev/null
+++ b/test/testdata/.hidden
@@ -0,0 +1 @@
+abandonned
diff --git a/test/testdata/abandonned.txt b/test/testdata/abandonned.txt
new file mode 100644
index 0000000..79726ff
--- /dev/null
+++ b/test/testdata/abandonned.txt
@@ -0,0 +1 @@
+abandoned
diff --git a/example/example.bin b/test/testdata/example.bin
similarity index 100%
rename from example/example.bin
rename to test/testdata/example.bin
diff --git a/example/example.txt b/test/testdata/example.txt
similarity index 68%
rename from example/example.txt
rename to test/testdata/example.txt
index 024f418..e1118f6 100644
--- a/example/example.txt
+++ b/test/testdata/example.txt
@@ -1,4 +1,4 @@
-abandonned
+1 abandonned 1
 Abandonned
 ABANDONNED
 AbAnDoNnEd
diff --git a/example/example:2.txt b/test/testdata/example:2.txt
similarity index 100%
rename from example/example:2.txt
rename to test/testdata/example:2.txt
diff --git a/test/testdata/subfolder/example.txt b/test/testdata/subfolder/example.txt
new file mode 100644
index 0000000..3eda6e1
--- /dev/null
+++ b/test/testdata/subfolder/example.txt
@@ -0,0 +1 @@
+abandonned