Provider Acceptance Test Patterns
Patterns for writing acceptance tests using terraform-plugin-testing with the Plugin Framework.
Source: HashiCorp Testing Patterns
References (load when needed):
-
references/checks.md — statecheck, plancheck, knownvalue types, tfjsonpath, comparers
-
references/sweepers.md — sweeper setup, TestMain, dependencies
-
references/ephemeral.md — ephemeral resource testing, echoprovider, multi-step patterns
Test Lifecycle
The framework runs each TestStep through: plan → apply → refresh → final plan. If the final plan shows a diff, the test fails (unless ExpectNonEmptyPlan is set). After all steps, destroy runs followed by CheckDestroy . This means every test automatically verifies that configurations apply cleanly and produce no drift — no assertions needed for that.
Test Function Structure
func TestAccExample_basic(t *testing.T) { var widget example.Widget rName := acctest.RandStringFromCharSet(10, acctest.CharSetAlphaNum) resourceName := "example_widget.test"
resource.ParallelTest(t, resource.TestCase{
PreCheck: func() { testAccPreCheck(t) },
ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
CheckDestroy: testAccCheckExampleDestroy,
Steps: []resource.TestStep{
{
Config: testAccExampleConfig_basic(rName),
ConfigStateChecks: []statecheck.StateCheck{
stateCheckExampleExists(resourceName, &widget),
statecheck.ExpectKnownValue(resourceName,
tfjsonpath.New("name"), knownvalue.StringExact(rName)),
statecheck.ExpectKnownValue(resourceName,
tfjsonpath.New("id"), knownvalue.NotNull()),
},
},
},
})
}
Use resource.ParallelTest by default. Use resource.Test only when tests share state or cannot run concurrently.
Provider Factory
// provider_test.go — Plugin Framework with Protocol 6 (use Protocol5 variant if needed) var testAccProtoV6ProviderFactories = map[string]func() (tfprotov6.ProviderServer, error){ "example": providerserver.NewProtocol6WithError(New("test")()), }
TestCase Fields
Field Purpose
PreCheck
func() — verify prerequisites (env vars, API access)
ProtoV6ProviderFactories
Plugin Framework provider factories
CheckDestroy
TestCheckFunc — verify resources destroyed after all steps
Steps
[]TestStep — sequential test operations
TerraformVersionChecks
[]tfversion.TerraformVersionCheck — gate by CLI version
TestStep Fields
Config Mode
Field Purpose
Config
Inline HCL string to apply
ConfigStateChecks
[]statecheck.StateCheck — modern assertions (preferred)
ConfigPlanChecks
resource.ConfigPlanChecks{PreApply: []plancheck.PlanCheck{...}}
ExpectError
*regexp.Regexp — expect failure matching pattern
ExpectNonEmptyPlan
bool — expect non-empty plan after apply
PlanOnly
bool — plan without applying
Destroy
bool — run destroy step
PreConfig
func() — setup before step
Import Mode
Field Purpose
ImportState
true to enable import mode
ImportStateVerify
Verify imported state matches prior state
ImportStateVerifyIgnore
[]string — attributes to skip during verify
ImportStateKind
resource.ImportBlockWithID — import block generation
ResourceName
Resource address to import
ImportStateId
Override the ID used for import
Check Functions
Modern: ConfigStateChecks (preferred)
Type-safe with aggregated error reporting. Compose built-in checks with custom statecheck.StateCheck implementations. See references/checks.md for full knownvalue types, tfjsonpath navigation, and comparers.
ConfigStateChecks: []statecheck.StateCheck{ stateCheckExampleExists(resourceName, &widget), statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("name"), knownvalue.StringExact("my-widget")), statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("enabled"), knownvalue.Bool(true)), statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("id"), knownvalue.NotNull()), statecheck.ExpectSensitiveValue(resourceName, tfjsonpath.New("api_key")), },
Do not mix Check (legacy) and ConfigStateChecks in the same step.
Legacy: Check (for CheckDestroy and migration)
CheckDestroy on TestCase requires TestCheckFunc . The Check field on TestStep also accepts TestCheckFunc but prefer ConfigStateChecks for new tests.
Check: resource.ComposeAggregateTestCheckFunc(
resource.TestCheckResourceAttr(name, "key", "expected"),
resource.TestCheckResourceAttrSet(name, "id"),
resource.TestCheckNoResourceAttr(name, "removed"),
resource.TestMatchResourceAttr(name, "url", regexp.MustCompile(^https://)),
resource.TestCheckResourceAttrPair(res1, "ref_id", res2, "id"),
),
ComposeAggregateTestCheckFunc reports all errors; ComposeTestCheckFunc
fails fast on the first.
Config Helpers
Use numbered format verbs — %[1]q for quoted strings, %[1]s for raw:
func testAccExampleConfig_basic(rName string) string {
return fmt.Sprintf(resource "example_widget" "test" { name = %[1]q }, rName)
}
func testAccExampleConfig_full(rName, description string) string {
return fmt.Sprintf(resource "example_widget" "test" { name = %[1]q description = %[2]q enabled = true }, rName, description)
}
Scenario Patterns
Basic + Update (combine in one test — updates are supersets of basic)
Steps: []resource.TestStep{ { Config: testAccExampleConfig_basic(rName), ConfigStateChecks: []statecheck.StateCheck{ stateCheckExampleExists(resourceName, &widget), statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("name"), knownvalue.StringExact(rName)), }, }, { Config: testAccExampleConfig_full(rName, "updated"), ConfigStateChecks: []statecheck.StateCheck{ stateCheckExampleExists(resourceName, &widget), statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("description"), knownvalue.StringExact("updated")), }, }, },
Import
After a config step, verify import produces identical state. Use ImportStateKind for import block generation:
{ ResourceName: resourceName, ImportState: true, ImportStateVerify: true, ImportStateKind: resource.ImportBlockWithID, },
Disappears (resource deleted externally)
{ Config: testAccExampleConfig_basic(rName), ConfigStateChecks: []statecheck.StateCheck{ stateCheckExampleExists(resourceName, &widget), stateCheckExampleDisappears(resourceName), }, ExpectNonEmptyPlan: true, },
Validation (expect error)
{
Config: testAccExampleConfig_invalidName(""),
ExpectError: regexp.MustCompile(name must not be empty),
},
Regression (two-commit workflow)
A proper bug fix uses at least two commits: first commit the regression test (which fails, confirming the bug), then commit the fix (test passes). This lets reviewers independently verify the test reproduces the issue by checking out the first commit, then advancing to the fix.
Name and document regression tests to identify the issue they fix. Include a link to the original bug report when possible.
// TestAccExample_regressionGH1234 verifies fix for https://github.com/org/repo/issues/1234 func TestAccExample_regressionGH1234(t *testing.T) { rName := acctest.RandStringFromCharSet(10, acctest.CharSetAlphaNum) resourceName := "example_widget.test"
resource.ParallelTest(t, resource.TestCase{
PreCheck: func() { testAccPreCheck(t) },
ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
CheckDestroy: testAccCheckExampleDestroy,
Steps: []resource.TestStep{
{
// Reproduce the issue: this config triggered the bug
Config: testAccExampleConfig_regressionGH1234(rName),
ConfigStateChecks: []statecheck.StateCheck{
stateCheckExampleExists(resourceName, nil),
statecheck.ExpectKnownValue(resourceName,
tfjsonpath.New("computed_field"), knownvalue.NotNull()),
},
},
},
})
}
Helper Functions
Custom StateCheck: Exists
Implement statecheck.StateCheck for API existence verification. Separate the exists check into its own function for reuse across steps — the source recommends this as a design principle:
type exampleExistsCheck struct { resourceAddress string widget *example.Widget }
func (e exampleExistsCheck) CheckState(ctx context.Context, req statecheck.CheckStateRequest, resp *statecheck.CheckStateResponse) { r, err := stateResourceAtAddress(req.State, e.resourceAddress) if err != nil { resp.Error = err return }
id, ok := r.AttributeValues["id"].(string)
if !ok {
resp.Error = fmt.Errorf("no id found for %s", e.resourceAddress)
return
}
conn := testAccAPIClient()
widget, err := conn.GetWidget(id)
if err != nil {
resp.Error = fmt.Errorf("%s not found via API: %w", e.resourceAddress, err)
return
}
if e.widget != nil {
*e.widget = *widget
}
}
func stateCheckExampleExists(name string, widget *example.Widget) statecheck.StateCheck { return exampleExistsCheck{resourceAddress: name, widget: widget} }
Custom StateCheck: Disappears
Delete a resource via API to simulate external deletion:
type exampleDisappearsCheck struct { resourceAddress string }
func (e exampleDisappearsCheck) CheckState(ctx context.Context, req statecheck.CheckStateRequest, resp *statecheck.CheckStateResponse) { r, err := stateResourceAtAddress(req.State, e.resourceAddress) if err != nil { resp.Error = err return }
id := r.AttributeValues["id"].(string)
conn := testAccAPIClient()
resp.Error = conn.DeleteWidget(id)
}
func stateCheckExampleDisappears(name string) statecheck.StateCheck { return exampleDisappearsCheck{resourceAddress: name} }
State Resource Lookup (shared utility)
func stateResourceAtAddress(state *tfjson.State, address string) (*tfjson.StateResource, error) { if state == nil || state.Values == nil || state.Values.RootModule == nil { return nil, fmt.Errorf("no state available") } for _, r := range state.Values.RootModule.Resources { if r.Address == address { return r, nil } } return nil, fmt.Errorf("not found in state: %s", address) }
Destroy Check (TestCheckFunc — required by CheckDestroy)
func testAccCheckExampleDestroy(s *terraform.State) error { conn := testAccAPIClient() for _, rs := range s.RootModule().Resources { if rs.Type != "example_widget" { continue } _, err := conn.GetWidget(rs.Primary.ID) if err == nil { return fmt.Errorf("widget %s still exists", rs.Primary.ID) } if !isNotFoundError(err) { return err } } return nil }
PreCheck
func testAccPreCheck(t *testing.T) { t.Helper() if os.Getenv("EXAMPLE_API_KEY") == "" { t.Fatal("EXAMPLE_API_KEY must be set for acceptance tests") } }