allow mocked values override during planning

internal/command/test_test.go

@@ -219,7 +219,7 @@ func TestTest_Runs(t *testing.T) {
 			code:        0,
 		},
 		"mocking": {
-			expectedOut: []string{"8 passed, 0 failed."},
+			expectedOut: []string{"9 passed, 0 failed."},
 			code:        0,
 		},
 		"mocking-invalid": {
@@ -232,7 +232,10 @@ func TestTest_Runs(t *testing.T) {
 		"mocking-error": {
 			expectedErr: []string{
 				"Unknown condition value",
+				"plan_mocked_overridden.tftest.hcl",
 				"test_resource.primary[0].id",
+				"plan_mocked_provider.tftest.hcl",
+				"test_resource.secondary[0].id",
 			},
 			code: 1,
 		},

internal/command/testdata/test/mocking-error/tests/plan_mocked_provider.tftest.hcl

@@ -0,0 +1,25 @@
+mock_provider "test" {
+  alias = "secondary"
+
+  mock_resource "test_resource" {
+    defaults = {
+      id = "ffff"
+    }
+  }
+}
+
+
+variables {
+  instances = 2
+  child_instances = 1
+}
+
+run "test" {
+  command = plan
+
+  assert {
+    condition = test_resource.secondary[0].id == "ffff"
+    error_message = "plan should use the mocked provider value when override_computed is true"
+  }
+
+}

internal/command/testdata/test/mocking/tests/plan_mocked_provider.tftest.hcl

@@ -0,0 +1,26 @@
+mock_provider "test" {
+  alias = "secondary"
+  override_computed = true
+
+  mock_resource "test_resource" {
+    defaults = {
+      id = "ffff"
+    }
+  }
+}
+
+
+variables {
+  instances = 2
+  child_instances = 1
+}
+
+run "test" {
+  command = plan
+
+  assert {
+    condition = test_resource.secondary[0].id == "ffff"
+    error_message = "plan should use the mocked provider value when override_computed is true"
+  }
+
+}

internal/configs/mock_provider.go

@@ -94,6 +94,14 @@ type MockData struct {
 	MockResources   map[string]*MockResource
 	MockDataSources map[string]*MockResource
 	Overrides       addrs.Map[addrs.Targetable, *Override]
+
+	useForPlan *bool // If true, the mock data can be used for planning.
+}
+
+// UseForPlan returns true if the provider-level setting for overrideComputed
+// is true, meaning that computed values can be overridden with the mocked values.
+func (data *MockData) UseForPlan() bool {
+	return data.useForPlan != nil && *data.useForPlan
 }
 
 // Merge will merge the target MockData object into the current MockData.
@@ -212,7 +220,7 @@ type Override struct {
 }
 
 // UseOverridesForPlan returns true if the computed values in the target
-// resource should be overridden with the values specified in the override block.
+// resource can be overridden with the values specified in the override block.
 func (o *Override) UseOverridesForPlan() bool {
 	return o.planComputedOverride != nil && *o.planComputedOverride
 }
@@ -231,6 +239,7 @@ func decodeMockDataBody(body hcl.Body, source OverrideSource) (*MockData, hcl.Di
 		MockResources:   make(map[string]*MockResource),
 		MockDataSources: make(map[string]*MockResource),
 		Overrides:       addrs.MakeMap[addrs.Targetable, *Override](),
+		useForPlan:      providerOverrideComputed,
 	}
 
 	for _, block := range content.Blocks {

internal/providers/mock.go

@@ -182,11 +182,18 @@ func (m *Mock) PlanResourceChange(request PlanResourceChangeRequest) PlanResourc
 			panic(fmt.Errorf("failed to retrieve schema for resource %s", request.TypeName))
 		}
 
-		// If the provider was overriden via override_* blocks, the mock provider is not called at all,
-		// so we can continue to make computed values as unknown here (until mock defaults support plan command).
-		value, diags := mocking.PlanComputedValuesForResource(request.ProposedNewState, &mocking.MockedData{
+		replacement := &mocking.MockedData{
+			Value:             cty.NilVal, // If we have no data then we use cty.NilVal.
 			ComputedAsUnknown: true,
-		}, resource.Block)
+		}
+		// if we are allowed to use the mock defaults for plan, we can populate the computed fields with the mock defaults.
+		if mockedResource, exists := m.Data.MockResources[request.TypeName]; exists && m.Data.UseForPlan() {
+			replacement.Value = mockedResource.Defaults
+			replacement.Range = mockedResource.DefaultsRange
+			replacement.ComputedAsUnknown = false
+		}
+
+		value, diags := mocking.PlanComputedValuesForResource(request.ProposedNewState, replacement, resource.Block)
 		response.Diagnostics = response.Diagnostics.Append(diags)
 		response.PlannedState = value
 		response.PlannedPrivate = []byte("create")