Allow functions in test mock blocks (#37883)

Author: dsa0x

.changes/v1.15/ENHANCEMENTS-20260113-130449.yaml

@@ -0,0 +1,5 @@
+kind: ENHANCEMENTS
+body: "Terraform Test: Allow functions within mock blocks"
+time: 2026-01-13T13:04:49.034917+01:00
+custom:
+  Issue: "34672"

internal/command/test_test.go

@@ -297,7 +297,6 @@ func TestTest_Runs(t *testing.T) {
 		},
 		"mocking-invalid": {
 			expectedErr: []string{
-				"Invalid outputs attribute",
 				"The override_during attribute must be a value of plan or apply.",
 			},
 			initCode: 1,
@@ -418,6 +417,21 @@ func TestTest_Runs(t *testing.T) {
 		"no-tests": {
 			code: 0,
 		},
+		"simple_pass_function": {
+			expectedOut:           []string{"2 passed, 0 failed."},
+			code:                  0,
+			expectedResourceCount: 0,
+		},
+		"mocking-invalid-outputs": {
+			expectedErr: []string{
+				"Invalid outputs attribute",
+			},
+			code: 1,
+		},
+		"mock-sources-inline": {
+			expectedOut: []string{"2 passed, 0 failed."},
+			code:        0,
+		},
 	}
 	for name, tc := range tcs {
 		t.Run(name, func(t *testing.T) {

internal/command/testdata/test/mock-sources-inline/main.tf

@@ -0,0 +1,27 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+provider "test" {
+  alias = "secondary"
+}
+
+resource "test_resource" "foo" {
+  value = "foo"
+}
+
+resource "test_resource" "bar" {
+  provider = test.secondary
+  value    = "bar"
+}
+
+output "foo" {
+  value = test_resource.foo.id
+}
+output "bar" {
+  value = test_resource.bar.id
+}

internal/command/testdata/test/mock-sources-inline/main.tftest.hcl

@@ -0,0 +1,30 @@
+
+mock_provider "test" {
+  source = "./testing/base"
+
+  mock_resource "test_resource" {
+    defaults = {
+      id = "local-mock-id" // should override the file-based mock
+    }
+  }
+}
+
+mock_provider "test" {
+  source = "./testing/base"
+  alias = "secondary"
+}
+
+run "test_foo" {
+  assert {
+    condition     = output.foo == "local-mock-id"
+    error_message = "invalid value"
+  }
+}
+
+
+run "test_bar" {
+  assert {
+    condition     = output.bar == "file-mock-id"
+    error_message = "invalid value"
+  }
+}

internal/command/testdata/test/mock-sources-inline/testing/base/.ignored.tfmock.hcl

@@ -0,0 +1,9 @@
+# If read, this file should cause issues. But, it should be ignored.
+
+mock_resource "test_resource" {}
+
+mock_data "test_resource" {}
+
+override_resource {
+  target = test_resource.foo
+}

internal/command/testdata/test/mock-sources-inline/testing/base/resource.tfmock.hcl

@@ -0,0 +1,5 @@
+mock_resource "test_resource" {
+  defaults = {
+    id = "file-mock-id"
+  }
+}

internal/command/testdata/test/mocking-invalid-outputs/main.tf

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+variable "instances" {
+  type = number
+}
+
+resource "test_resource" "primary" {
+  count = var.instances
+}

internal/command/testdata/test/mocking-invalid-outputs/tests/module_mocked_invalid_type.tftest.hcl

@@ -0,0 +1,12 @@
+override_resource {
+  target  = test_resource.primary
+  values = "should be an object" // invalid
+}
+
+variables {
+  instances = 2
+}
+
+run "test" {
+  # We won't even execute this, as the configuration isn't valid.
+}

internal/command/testdata/test/simple_pass_function/main.tf

@@ -0,0 +1,7 @@
+resource "test_resource" "foo" {
+  value = "foo"
+}
+
+resource "test_resource" "bar" {
+  value = "bar"
+}

internal/command/testdata/test/simple_pass_function/main.tftest.hcl

@@ -0,0 +1,28 @@
+mock_provider "test" {
+  mock_resource "test_resource" {
+    defaults = {
+      id = format("f-%s", "foo")
+    }
+  }
+}
+
+override_resource {
+  target = test_resource.bar
+  values = {
+    id = format("%s-%s", uuid(), "bar")
+  }
+}
+
+run "validate_test_resource_foo" {
+  assert {
+    condition = test_resource.foo.id == "f-foo"
+    error_message = "invalid value"
+  }
+}
+
+run "validate_test_resource_bar" {
+  assert {
+    condition = length(test_resource.bar.id) > 10
+    error_message = "invalid value"
+  }
+}