diff --git a/.github/workflows/test-test.yaml b/.github/workflows/test-test.yaml
new file mode 100644
index 00000000..bd13ef55
--- /dev/null
+++ b/.github/workflows/test-test.yaml
@@ -0,0 +1,155 @@
+name: Test terraform-test
+
+on:
+  - push
+
+jobs:
+  default:
+    runs-on: ubuntu-latest
+    name: Default inputs
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Test
+        uses: ./terraform-test
+        id: test
+        with:
+          path: tests/workflows/test-test/local
+
+      - name: Check Passed
+        run: |
+          if [[ "${{ steps.test.outputs.failure-reason }}" != "" ]]; then
+            echo "::error:: failure-reason not set correctly"
+            exit 1
+          fi
+
+  filter:
+    runs-on: ubuntu-latest
+    name: Default path with a filter
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Test
+        uses: ./terraform-test
+        id: test
+        with:
+          path: tests/workflows/test-test/local
+          test_filter: tests/main.tftest.hcl
+
+      - name: Check Passed
+        run: |
+          if [[ "${{ steps.test.outputs.failure-reason }}" != "" ]]; then
+            echo "::error:: failure-reason not set correctly"
+            exit 1
+          fi
+
+  test_dir:
+    runs-on: ubuntu-latest
+    name: Custom test directory
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Test
+        uses: ./terraform-test
+        id: test
+        with:
+          path: tests/workflows/test-test/local
+          test_directory: custom-test-dir
+          test_filter: |
+            custom-test-dir/another.tftest.hcl
+            custom-test-dir/a-third.tftest.hcl
+
+      - name: Check Passed
+        run: |
+          if [[ "${{ steps.test.outputs.failure-reason }}" != "" ]]; then
+            echo "::error:: failure-reason not set correctly"
+            exit 1
+          fi
+
+  nonexistent_test_dir:
+    runs-on: ubuntu-latest
+    name: Missing test directory
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Test
+        uses: ./terraform-test
+        id: nonexistent_test_dir
+        continue-on-error: true
+        with:
+          path: tests/workflows/test-test/local
+          test_directory: i-dont-exist
+
+      - name: Check failure
+        run: |
+          if [[ "${{ steps.nonexistent_test_dir.outcome }}" != "failure" ]]; then
+            echo "Test did not fail correctly"
+            exit 1
+          fi
+
+          if [[ "${{ steps.nonexistent_test_dir.outputs.failure-reason }}" != "no-tests" ]]; then
+            echo "::error:: failure-reason not set correctly"
+            exit 1
+          fi
+
+  faulty_filter:
+    runs-on: ubuntu-latest
+    name: Filter matches no tests
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Test
+        uses: ./terraform-test
+        id: faulty_filter
+        continue-on-error: true
+        with:
+          path: tests/workflows/test-test/local
+          test_filter: |
+            tests/this-test-does-not-exist.tftest.hcl
+            tests/nor-does-this-one.tftest.hcl
+
+      - name: Check failure
+        run: |
+          if [[ "${{ steps.faulty_filter.outcome }}" != "failure" ]]; then
+            echo "Test did not fail correctly"
+            exit 1
+          fi
+
+          if [[ "${{ steps.faulty_filter.outputs.failure-reason }}" != "no-tests" ]]; then
+            echo "::error:: failure-reason not set correctly"
+            exit 1
+          fi
+
+  failing:
+    runs-on: ubuntu-latest
+    name: A failing test using variables
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Test
+        uses: ./terraform-test
+        id: failing
+        continue-on-error: true
+        with:
+          path: tests/workflows/test-test/local
+          test_filter: tests/main.tftest.hcl
+          variables: |
+            length = 1
+
+      - name: Check failure-reason
+        run: |
+          if [[ "${{ steps.failing.outcome }}" != "failure" ]]; then
+            echo "Test did not fail correctly"
+            exit 1
+          fi
+          
+          if [[ "${{ steps.failing.outputs.failure-reason }}" != "tests-failed" ]]; then
+            echo "::error:: failure-reason not set correctly"
+            exit 1
+          fi
diff --git a/CHANGELOG.md b/CHANGELOG.md
index db21b057..c9c44c89 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -668,7 +668,7 @@ First release of the GitHub Actions:
 - [dflook/terraform-new-workspace](terraform-new-workspace)
 - [dflook/terraform-destroy-workspace](terraform-destroy-workspace)
 
-[1.42.0]: https://github.com/dflook/terraform-github-actions/compare/v1.42.0...v1.42.1
+[1.42.1]: https://github.com/dflook/terraform-github-actions/compare/v1.42.0...v1.42.1
 [1.42.0]: https://github.com/dflook/terraform-github-actions/compare/v1.41.2...v1.42.0
 [1.41.2]: https://github.com/dflook/terraform-github-actions/compare/v1.41.1...v1.41.2
 [1.41.1]: https://github.com/dflook/terraform-github-actions/compare/v1.41.0...v1.41.1
diff --git a/image/actions.sh b/image/actions.sh
index 64750749..35624948 100644
--- a/image/actions.sh
+++ b/image/actions.sh
@@ -176,6 +176,26 @@ function init() {
     end_group
 }
 
+##
+# Initialize terraform for running tests
+#
+# This installs modules and providers for the module and all tests
+function init-test() {
+    start_group "Initializing $TOOL_PRODUCT_NAME"
+
+    rm -rf "$TF_DATA_DIR"
+
+    if [[ -n "$INPUT_TEST_DIRECTORY" ]]; then
+        debug_log $TOOL_COMMAND_NAME init -input=false -backend=false -test-directory "$INPUT_TEST_DIRECTORY"
+        (cd "$INPUT_PATH" && $TOOL_COMMAND_NAME init -input=false -backend=false -test-directory $INPUT_TEST_DIRECTORY)
+    else
+        debug_log $TOOL_COMMAND_NAME init -input=false -backend=false
+        (cd "$INPUT_PATH" && $TOOL_COMMAND_NAME init -input=false -backend=false)
+    fi
+
+    end_group
+}
+
 function set-init-args() {
     INIT_ARGS=""
 
@@ -339,15 +359,7 @@ function set-common-plan-args() {
     fi
 }
 
-function set-plan-args() {
-    set-common-plan-args
-
-    if [[ -n "$INPUT_VAR" ]]; then
-        for var in $(echo "$INPUT_VAR" | tr ',' '\n'); do
-            PLAN_ARGS="$PLAN_ARGS -var $var"
-        done
-    fi
-
+function set-variable-args() {
     if [[ -n "$INPUT_VAR_FILE" ]]; then
         for file in $(echo "$INPUT_VAR_FILE" | tr ',' '\n'); do
 
@@ -364,6 +376,18 @@ function set-plan-args() {
         echo "$INPUT_VARIABLES" >"$STEP_TMP_DIR/variables.tfvars"
         PLAN_ARGS="$PLAN_ARGS -var-file=$STEP_TMP_DIR/variables.tfvars"
     fi
+}
+
+function set-plan-args() {
+    set-common-plan-args
+
+    if [[ -n "$INPUT_VAR" ]]; then
+        for var in $(echo "$INPUT_VAR" | tr ',' '\n'); do
+            PLAN_ARGS="$PLAN_ARGS -var $var"
+        done
+    fi
+
+    set-variable-args
 
     export PLAN_ARGS
 }
diff --git a/image/entrypoints/test.sh b/image/entrypoints/test.sh
new file mode 100755
index 00000000..1a58a8e3
--- /dev/null
+++ b/image/entrypoints/test.sh
@@ -0,0 +1,65 @@
+#!/bin/bash
+
+# shellcheck source=../actions.sh
+source /usr/local/actions.sh
+
+debug
+setup
+init-test
+
+exec 3>&1
+
+function set-test-args() {
+    TEST_ARGS=""
+
+    if [[ -v INPUT_CLOUD_RUN && -n "$INPUT_CLOUD_RUN" ]]; then
+        # I have no idea what this does, it is not well documented.
+        TEST_ARGS="$TEST_ARGS -cloud-run=$INPUT_CLOUD_RUN"
+    fi
+
+    if [[ -n "$INPUT_TEST_DIRECTORY" ]]; then
+        TEST_ARGS="$TEST_ARGS -test-directory=$INPUT_TEST_DIRECTORY"
+    fi
+
+    if [[ -n "$INPUT_TEST_FILTER" ]]; then
+        for file in $(echo "$INPUT_TEST_FILTER" | tr ',' '\n'); do
+            TEST_ARGS="$TEST_ARGS -filter=$file"
+        done
+    fi
+}
+
+function test() {
+
+    debug_log $TOOL_COMMAND_NAME test -no-color $TEST_ARGS '$PLAN_ARGS'  # don't expand PLAN_ARGS
+
+    set +e
+    # shellcheck disable=SC2086
+    (cd "$INPUT_PATH" && $TOOL_COMMAND_NAME test -no-color $TEST_ARGS $PLAN_ARGS) \
+        2>"$STEP_TMP_DIR/terraform_test.stderr" \
+        | tee /dev/fd/3 \
+            >"$STEP_TMP_DIR/terraform_test.stdout"
+
+    # shellcheck disable=SC2034
+    TEST_EXIT=${PIPESTATUS[0]}
+    set -e
+
+    cat "$STEP_TMP_DIR/terraform_test.stderr"
+
+    if [[ $TEST_EXIT -eq 0 ]]; then
+        # Workaround a bit of stupidity in the terraform test command
+        if grep -q "Success! 0 passed, 0 failed." "$STEP_TMP_DIR/terraform_test.stdout"; then
+            error_log "No tests found"
+            set_output failure-reason no-tests
+            exit 1
+        fi
+    else
+        set_output failure-reason tests-failed
+        exit 1
+    fi
+}
+
+set-test-args
+PLAN_ARGS=""
+set-variable-args
+
+test
diff --git a/terraform-test/README.md b/terraform-test/README.md
new file mode 100644
index 00000000..0ff3ddfe
--- /dev/null
+++ b/terraform-test/README.md
@@ -0,0 +1,208 @@
+# terraform-test action
+
+This is one of a suite of Terraform related actions - find them at [dflook/terraform-github-actions](https://github.com/dflook/terraform-github-actions).
+
+Execute automated tests on a Terraform module using the built-in `terraform test` command.
+
+## Inputs
+
+* `path`
+
+  Path to the Terraform module under test
+
+  - Type: string
+  - Optional
+  - Default: The action workspace
+
+* `test_directory`
+
+  The directory within the module path that contains the test files.
+
+  ```yaml
+  with:
+    test_directory: tf_tests
+  ```
+
+  - Type: string
+  - Optional
+  - Default: `tests`
+
+* `test_filter`
+
+  The test files to run, one per line.
+  
+  If not specified, all test files in the `test_directory` will be run.
+  The are paths relative to the module path.
+
+  ```yaml
+  with:
+    test_filter: |
+      tests/main.tftest.hcl
+      tests/other.tftest.hcl
+  ```
+
+  - Type: string
+  - Optional
+  - Default: All test files in the `test_directory`
+
+* `variables`
+
+  Variables to set for the tests. This should be valid Terraform syntax - like a [variable definition file](https://www.terraform.io/docs/language/values/variables.html#variable-definitions-tfvars-files).
+
+  ```yaml
+  with:
+    variables: |
+      image_id = "${{ secrets.AMI_ID }}"
+      availability_zone_names = [
+        "us-east-1a",
+        "us-west-1c",
+      ]
+  ```
+
+  Variables set here override any given in `var_file`s.
+
+  - Type: string
+  - Optional
+
+* `var_file`
+
+  List of tfvars files to use, one per line.
+  Paths should be relative to the GitHub Actions workspace
+  
+  ```yaml
+  with:
+    var_file: |
+      common.tfvars
+      prod.tfvars
+  ```
+
+  - Type: string
+  - Optional
+
+## Outputs
+
+* `failure-reason`
+
+  When the job outcome is `failure`, this output may be set. The value may be one of:
+
+  - `no-tests` - No tests were found to run.
+  - `tests-failed` - One or more tests failed.
+
+  If the job fails for any other reason this will not be set.
+  This can be used with the Actions expression syntax to conditionally run steps.
+
+## Environment Variables
+
+* `GITHUB_DOT_COM_TOKEN`
+
+  This is used to specify a token for GitHub.com when the action is running on a GitHub Enterprise instance.
+  This is only used for downloading OpenTofu binaries from GitHub.com.
+  If this is not set, an unauthenticated request will be made to GitHub.com to download the binary, which may be rate limited.
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_CLOUD_TOKENS`
+
+  API tokens for cloud hosts, of the form `<host>=<token>`. Multiple tokens may be specified, one per line.
+  These tokens may be used with the `remote` backend and for fetching required modules from the registry.
+
+  e.g:
+  ```yaml
+  env:
+    TERRAFORM_CLOUD_TOKENS: app.terraform.io=${{ secrets.TF_CLOUD_TOKEN }}
+  ```
+
+  With other registries:
+  ```yaml
+  env:
+    TERRAFORM_CLOUD_TOKENS: |
+      app.terraform.io=${{ secrets.TF_CLOUD_TOKEN }}
+      terraform.example.com=${{ secrets.TF_REGISTRY_TOKEN }}
+  ```
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_SSH_KEY`
+
+  A SSH private key that Terraform will use to fetch git/mercurial module sources.
+
+  This should be in PEM format.
+
+  For example:
+  ```yaml
+  env:
+    TERRAFORM_SSH_KEY: ${{ secrets.TERRAFORM_SSH_KEY }}
+  ```
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_HTTP_CREDENTIALS`
+
+  Credentials that will be used for fetching modules sources with `git::http://`, `git::https://`, `http://` & `https://` schemes.
+
+  Credentials have the format `<host>=<username>:<password>`. Multiple credentials may be specified, one per line.
+
+  Each credential is evaluated in order, and the first matching credentials are used. 
+
+  Credentials that are used by git (`git::http://`, `git::https://`) allow a path after the hostname.
+  Paths are ignored by `http://` & `https://` schemes.
+  For git module sources, a credential matches if each mentioned path segment is an exact match.
+
+  For example:
+  ```yaml
+  env:
+    TERRAFORM_HTTP_CREDENTIALS: |
+      example.com=dflook:${{ secrets.HTTPS_PASSWORD }}
+      github.com/dflook/terraform-github-actions.git=dflook-actions:${{ secrets.ACTIONS_PAT }}
+      github.com/dflook=dflook:${{ secrets.DFLOOK_PAT }}
+      github.com=graham:${{ secrets.GITHUB_PAT }}  
+  ```
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_PRE_RUN`
+
+  A set of commands that will be ran prior to `terraform init`. This can be used to customise the environment before running Terraform. 
+  
+  The runtime environment for these actions is subject to change in minor version releases. If using this environment variable, specify the minor version of the action to use.
+  
+  The runtime image is currently based on `debian:bullseye`, with the command run using `bash -xeo pipefail`.
+
+  For example:
+  ```yaml
+  env:
+    TERRAFORM_PRE_RUN: |
+      # Install latest Azure CLI
+      curl -skL https://aka.ms/InstallAzureCLIDeb | bash
+      
+      # Install postgres client
+      apt-get install -y --no-install-recommends postgresql-client
+  ```
+
+  - Type: string
+  - Optional
+
+## Example usage
+
+```yaml
+name: "Run Tests"
+
+on: [push]
+
+jobs:
+  test:
+    name: Unlock
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout current branch
+        uses: actions/checkout@v3
+
+      - name: Terraform Tests
+        uses: dflook/terraform-test@v1
+        with:
+          path: modules/vpc
+```
diff --git a/terraform-test/action.yaml b/terraform-test/action.yaml
new file mode 100644
index 00000000..06f69c86
--- /dev/null
+++ b/terraform-test/action.yaml
@@ -0,0 +1,36 @@
+name: terraform-test
+description: Execute automated tests for a Terraform module
+author: Daniel Flook
+
+inputs:
+  path:
+    description: Path to the Terraform module under test
+    required: false
+    default: .
+  test_directory:
+    description: Path to the Terraform tests
+    required: false
+    default: ""
+  test_filter:
+    description: Test files to run within the test_directory
+    required: false
+    default: ""
+  variables:
+    description: Variable definitions
+    required: false
+  var_file:
+    description: List of var file paths, one per line
+    required: false
+
+outputs:
+  failure-reason:
+    description: The reason for the build failure. May be `no-tests` or `tests-failed`.
+
+runs:
+  using: docker
+  image: ../image/Dockerfile
+  entrypoint: /entrypoints/test.sh
+
+branding:
+  icon: globe
+  color: purple
diff --git a/tests/workflows/test-test/local/custom-test-dir/a-third.tftest.hcl b/tests/workflows/test-test/local/custom-test-dir/a-third.tftest.hcl
new file mode 100644
index 00000000..988d59a9
--- /dev/null
+++ b/tests/workflows/test-test/local/custom-test-dir/a-third.tftest.hcl
@@ -0,0 +1,21 @@
+run "require_provider" {
+  # This will require terraform to be initialised correctly to bring in the time provider
+  command = apply
+
+  module {
+    source = "./sleep"
+  }
+}
+
+run "test_third" {
+  command = apply
+
+  variables {
+    length = 15
+  }
+
+  assert {
+    condition     = length(output.random_string) == 15
+    error_message = "Length is not correct"
+  }
+}
diff --git a/tests/workflows/test-test/local/custom-test-dir/another.tftest.hcl b/tests/workflows/test-test/local/custom-test-dir/another.tftest.hcl
new file mode 100644
index 00000000..a8d5195d
--- /dev/null
+++ b/tests/workflows/test-test/local/custom-test-dir/another.tftest.hcl
@@ -0,0 +1,12 @@
+run "test_length" {
+  command = apply
+
+  variables {
+    length = 12
+  }
+
+  assert {
+    condition     = length(output.random_string) == 12
+    error_message = "Length is not correct"
+  }
+}
diff --git a/tests/workflows/test-test/local/custom-test-dir/main.tftest.hcl b/tests/workflows/test-test/local/custom-test-dir/main.tftest.hcl
new file mode 100644
index 00000000..dc8808d2
--- /dev/null
+++ b/tests/workflows/test-test/local/custom-test-dir/main.tftest.hcl
@@ -0,0 +1,12 @@
+run "test_length" {
+  command = apply
+
+  variables {
+    length = 11
+  }
+
+  assert {
+    condition     = length(output.random_string) == 11
+    error_message = "Length is not correct"
+  }
+}
diff --git a/tests/workflows/test-test/local/main.tf b/tests/workflows/test-test/local/main.tf
new file mode 100644
index 00000000..afd915cc
--- /dev/null
+++ b/tests/workflows/test-test/local/main.tf
@@ -0,0 +1,14 @@
+variable "length" {
+  description = "The length of the string"
+  type        = number
+  default     = 10
+}
+
+resource "random_string" "example" {
+  length  = var.length
+  special = false
+}
+
+output "random_string" {
+  value = random_string.example.result
+}
diff --git a/tests/workflows/test-test/local/sleep/main.tf b/tests/workflows/test-test/local/sleep/main.tf
new file mode 100644
index 00000000..e5913152
--- /dev/null
+++ b/tests/workflows/test-test/local/sleep/main.tf
@@ -0,0 +1,3 @@
+resource "time_sleep" "this" {
+  create_duration = "1s"
+}
\ No newline at end of file
diff --git a/tests/workflows/test-test/local/tests/another.tftest.hcl b/tests/workflows/test-test/local/tests/another.tftest.hcl
new file mode 100644
index 00000000..e2f60480
--- /dev/null
+++ b/tests/workflows/test-test/local/tests/another.tftest.hcl
@@ -0,0 +1,12 @@
+run "test_length" {
+  command = apply
+
+  variables {
+    length = 13
+  }
+
+  assert {
+    condition     = length(output.random_string) == 13
+    error_message = "Length is not correct"
+  }
+}
diff --git a/tests/workflows/test-test/local/tests/main.tftest.hcl b/tests/workflows/test-test/local/tests/main.tftest.hcl
new file mode 100644
index 00000000..0aec8843
--- /dev/null
+++ b/tests/workflows/test-test/local/tests/main.tftest.hcl
@@ -0,0 +1,8 @@
+run "test" {
+  command = apply
+
+  assert {
+    condition     = length(output.random_string) == 10
+    error_message = "Length is not correct"
+  }
+}
diff --git a/tofu-test/README.md b/tofu-test/README.md
new file mode 100644
index 00000000..9569260c
--- /dev/null
+++ b/tofu-test/README.md
@@ -0,0 +1,208 @@
+# tofu-test action
+
+This is one of a suite of OpenTofu related actions - find them at [dflook/terraform-github-actions](https://github.com/dflook/terraform-github-actions).
+
+Execute automated tests on an OpenTofu module using the built-in `tofu test` command.
+
+## Inputs
+
+* `path`
+
+  Path to the OpenTofu module under test
+
+  - Type: string
+  - Optional
+  - Default: The action workspace
+
+* `test_directory`
+
+  The directory within the module path that contains the test files.
+
+  ```yaml
+  with:
+    test_directory: tf_tests
+  ```
+
+  - Type: string
+  - Optional
+  - Default: `tests`
+
+* `test_filter`
+
+  The test files to run, one per line.
+  
+  If not specified, all test files in the `test_directory` will be run.
+  The are paths relative to the module path.
+
+  ```yaml
+  with:
+    test_filter: |
+      tests/main.tftest.hcl
+      tests/other.tftest.hcl
+  ```
+
+  - Type: string
+  - Optional
+  - Default: All test files in the `test_directory`
+
+* `variables`
+
+  Variables to set for the tests. This should be valid OpenTofu syntax - like a [variable definition file](https://www.terraform.io/docs/language/values/variables.html#variable-definitions-tfvars-files).
+
+  ```yaml
+  with:
+    variables: |
+      image_id = "${{ secrets.AMI_ID }}"
+      availability_zone_names = [
+        "us-east-1a",
+        "us-west-1c",
+      ]
+  ```
+
+  Variables set here override any given in `var_file`s.
+
+  - Type: string
+  - Optional
+
+* `var_file`
+
+  List of tfvars files to use, one per line.
+  Paths should be relative to the GitHub Actions workspace
+  
+  ```yaml
+  with:
+    var_file: |
+      common.tfvars
+      prod.tfvars
+  ```
+
+  - Type: string
+  - Optional
+
+## Outputs
+
+* `failure-reason`
+
+  When the job outcome is `failure`, this output may be set. The value may be one of:
+
+  - `no-tests` - No tests were found to run.
+  - `tests-failed` - One or more tests failed.
+
+  If the job fails for any other reason this will not be set.
+  This can be used with the Actions expression syntax to conditionally run steps.
+
+## Environment Variables
+
+* `GITHUB_DOT_COM_TOKEN`
+
+  This is used to specify a token for GitHub.com when the action is running on a GitHub Enterprise instance.
+  This is only used for downloading OpenTofu binaries from GitHub.com.
+  If this is not set, an unauthenticated request will be made to GitHub.com to download the binary, which may be rate limited.
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_CLOUD_TOKENS`
+
+  API tokens for cloud hosts, of the form `<host>=<token>`. Multiple tokens may be specified, one per line.
+  These tokens may be used with the `remote` backend and for fetching required modules from the registry.
+
+  e.g:
+  ```yaml
+  env:
+    TERRAFORM_CLOUD_TOKENS: app.terraform.io=${{ secrets.TF_CLOUD_TOKEN }}
+  ```
+
+  With other registries:
+  ```yaml
+  env:
+    TERRAFORM_CLOUD_TOKENS: |
+      app.terraform.io=${{ secrets.TF_CLOUD_TOKEN }}
+      tofu.example.com=${{ secrets.TF_REGISTRY_TOKEN }}
+  ```
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_SSH_KEY`
+
+  A SSH private key that OpenTofu will use to fetch git/mercurial module sources.
+
+  This should be in PEM format.
+
+  For example:
+  ```yaml
+  env:
+    TERRAFORM_SSH_KEY: ${{ secrets.TERRAFORM_SSH_KEY }}
+  ```
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_HTTP_CREDENTIALS`
+
+  Credentials that will be used for fetching modules sources with `git::http://`, `git::https://`, `http://` & `https://` schemes.
+
+  Credentials have the format `<host>=<username>:<password>`. Multiple credentials may be specified, one per line.
+
+  Each credential is evaluated in order, and the first matching credentials are used. 
+
+  Credentials that are used by git (`git::http://`, `git::https://`) allow a path after the hostname.
+  Paths are ignored by `http://` & `https://` schemes.
+  For git module sources, a credential matches if each mentioned path segment is an exact match.
+
+  For example:
+  ```yaml
+  env:
+    TERRAFORM_HTTP_CREDENTIALS: |
+      example.com=dflook:${{ secrets.HTTPS_PASSWORD }}
+      github.com/dflook/terraform-github-actions.git=dflook-actions:${{ secrets.ACTIONS_PAT }}
+      github.com/dflook=dflook:${{ secrets.DFLOOK_PAT }}
+      github.com=graham:${{ secrets.GITHUB_PAT }}  
+  ```
+
+  - Type: string
+  - Optional
+
+* `TERRAFORM_PRE_RUN`
+
+  A set of commands that will be ran prior to `tofu init`. This can be used to customise the environment before running OpenTofu. 
+  
+  The runtime environment for these actions is subject to change in minor version releases. If using this environment variable, specify the minor version of the action to use.
+  
+  The runtime image is currently based on `debian:bullseye`, with the command run using `bash -xeo pipefail`.
+
+  For example:
+  ```yaml
+  env:
+    TERRAFORM_PRE_RUN: |
+      # Install latest Azure CLI
+      curl -skL https://aka.ms/InstallAzureCLIDeb | bash
+      
+      # Install postgres client
+      apt-get install -y --no-install-recommends postgresql-client
+  ```
+
+  - Type: string
+  - Optional
+
+## Example usage
+
+```yaml
+name: "Run Tests"
+
+on: [push]
+
+jobs:
+  test:
+    name: Unlock
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout current branch
+        uses: actions/checkout@v3
+
+      - name: OpenTofu Tests
+        uses: dflook/tofu-test@v1
+        with:
+          path: modules/vpc
+```
diff --git a/tofu-test/action.yaml b/tofu-test/action.yaml
new file mode 100644
index 00000000..0b8dafe4
--- /dev/null
+++ b/tofu-test/action.yaml
@@ -0,0 +1,38 @@
+name: tofu-test
+description: Execute automated tests for an OpenTofu module
+author: Daniel Flook
+
+inputs:
+  path:
+    description: Path to the OpenTofu module under test
+    required: false
+    default: .
+  test_directory:
+    description: Path to the OpenTofu tests
+    required: false
+    default: ""
+  test_filter:
+    description: Test files to run within the test_directory
+    required: false
+    default: ""
+  variables:
+    description: Variable definitions
+    required: false
+  var_file:
+    description: List of var file paths, one per line
+    required: false
+
+outputs:
+  failure-reason:
+    description: The reason for the build failure. May be `no-tests` or `tests-failed`.
+
+runs:
+  env:
+    OPENTOFU: true
+  using: docker
+  image: ../image/Dockerfile
+  entrypoint: /entrypoints/test.sh
+
+branding:
+  icon: globe
+  color: purple