retain legacy behaviour of empty collection when given an object as mock

internal/command/test_test.go

@@ -5674,21 +5674,52 @@ func TestTest_TeardownOrder(t *testing.T) {
 	}
 }
 
-func TestTest_OverrideDataListAttribute(t *testing.T) {
+func TestTest_OverrideDataMocking(t *testing.T) {
 	tcs := map[string]struct {
-		dir  string
-		code int
-		desc string
+		dir            string
+		expectedCode   int
+		expectedStdout string
+		expectedStderr string
 	}{
 		"plain_list_attribute": {
-			dir:  "override_data_list_attribute",
-			code: 0,
-			desc: "override_data with a computed cty.List(cty.Object) attribute",
+			dir:            "override_data_list_attribute",
+			expectedCode:   0,
+			expectedStdout: "1 passed, 0 failed.",
 		},
 		"nested_list_attribute": {
-			dir:  "override_data_nested_list_attribute",
-			code: 0,
-			desc: "override_data with a computed NestedType NestingList attribute",
+			dir:            "override_data_nested_list_attribute",
+			expectedCode:   0,
+			expectedStdout: "1 passed, 0 failed.",
+		},
+		"nested_list_attribute_with_object_value": {
+			dir:            "override_data_nested_list_attribute_object",
+			expectedCode:   0,
+			expectedStdout: "1 passed, 0 failed.",
+		},
+		"nested_list_attribute_with_invalid_type_value": {
+			dir:            "override_data_nested_list_attribute_invalid_type",
+			expectedCode:   1,
+			expectedStderr: "incompatible types; expected list of object, found",
+		},
+		"list_attribute_with_partial_element_values": {
+			dir:            "override_data_list_attribute_partial_elements",
+			expectedCode:   0,
+			expectedStdout: "1 passed, 0 failed.",
+		},
+		"set_attribute_with_partial_element_values": {
+			dir:            "override_data_complex_set_attribute_partial_elements",
+			expectedCode:   0,
+			expectedStdout: "1 passed, 0 failed.",
+		},
+		"nested_set_attribute_with_object_value": {
+			dir:            "override_data_complex_nested_set_attribute_object",
+			expectedCode:   0,
+			expectedStdout: "1 passed, 0 failed.",
+		},
+		"nested_list_attribute_with_partial_element_values": {
+			dir:            "override_data_nested_list_attribute_partial_elements",
+			expectedCode:   0,
+			expectedStdout: "1 passed, 0 failed.",
 		},
 	}
 
@@ -5725,7 +5756,6 @@ func TestTest_OverrideDataListAttribute(t *testing.T) {
 				t.Fatalf("expected init status code 0 but got %d: %s", code, output.All())
 			}
 
-			// Reset the streams for the next command.
 			streams, done = terminal.StreamsForTesting(t)
 			meta.Streams = streams
 			meta.View = views.NewView(streams)
@@ -5737,17 +5767,20 @@ func TestTest_OverrideDataListAttribute(t *testing.T) {
 			code := c.Run([]string{"-no-color"})
 			output := done(t)
 
-			if code != tc.code {
-				t.Errorf("expected status code %d but got %d:\n\n%s", tc.code, code, output.All())
+			if code != tc.expectedCode {
+				t.Fatalf("expected status code %d but got %d:\n\n%s", tc.expectedCode, code, output.All())
 			}
 
-			if tc.code == 0 {
-				if !strings.Contains(output.Stdout(), "1 passed, 0 failed.") {
-					t.Errorf("expected passing test output but got:\n\nstdout:\n%s\nstderr:\n%s", output.Stdout(), output.Stderr())
-				}
-				if output.Stderr() != "" {
-					t.Errorf("unexpected stderr output:\n%s", output.Stderr())
-				}
+			if tc.expectedStdout != "" && !strings.Contains(output.Stdout(), tc.expectedStdout) {
+				t.Errorf("expected stdout to contain %q but got:\n\nstdout:\n%s\nstderr:\n%s", tc.expectedStdout, output.Stdout(), output.Stderr())
+			}
+
+			if tc.expectedStderr != "" && !strings.Contains(output.Stderr(), tc.expectedStderr) {
+				t.Errorf("expected stderr to contain %q but got:\n\nstdout:\n%s\nstderr:\n%s", tc.expectedStderr, output.Stdout(), output.Stderr())
+			}
+
+			if tc.expectedCode == 0 && output.Stderr() != "" {
+				t.Errorf("unexpected stderr output:\n%s", output.Stderr())
 			}
 		})
 	}

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

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+data "test_complex_data_source" "datasource" {
+  id = "resource"
+}
+
+output "nested_set_value" {
+  value = data.test_complex_data_source.datasource.nested_set_value
+}

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

@@ -0,0 +1,19 @@
+provider "test" {}
+
+override_data {
+  target = data.test_complex_data_source.datasource
+  values = {
+    nested_set_value = {
+      name = "shared"
+    }
+  }
+}
+
+run "test_override_data_complex_nested_set_attribute_object" {
+  command = plan
+
+  assert {
+    condition     = length(data.test_complex_data_source.datasource.nested_set_value) == 0
+    error_message = "Expected nested_set_value to be empty when overridden with an object"
+  }
+}

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

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+data "test_complex_data_source" "datasource" {
+  id = "resource"
+}
+
+output "set_value" {
+  value = data.test_complex_data_source.datasource.set_value
+}

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

@@ -0,0 +1,40 @@
+provider "test" {}
+
+override_data {
+  target = data.test_complex_data_source.datasource
+  values = {
+    set_value = [
+      {
+        name = "first"
+      },
+      {
+        value = "two"
+      },
+    ]
+  }
+}
+
+run "test_override_data_complex_set_attribute_partial_elements" {
+  command = plan
+
+  assert {
+    condition     = length(data.test_complex_data_source.datasource.set_value) == 2
+    error_message = "Expected set_value to have 2 elements, got ${length(data.test_complex_data_source.datasource.set_value)}"
+  }
+
+  assert {
+    condition = length([
+      for item in data.test_complex_data_source.datasource.set_value : item
+      if item.name == "first" && item.value != null
+    ]) == 1
+    error_message = "Expected one set_value element with name 'first' and a filled-in value"
+  }
+
+  assert {
+    condition = length([
+      for item in data.test_complex_data_source.datasource.set_value : item
+      if item.value == "two" && item.name != null
+    ]) == 1
+    error_message = "Expected one set_value element with value 'two' and a filled-in name"
+  }
+}

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

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+data "test_data_source" "datasource" {
+  id = "resource"
+}
+
+output "list_value" {
+  value = data.test_data_source.datasource.list_value
+}

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

@@ -0,0 +1,44 @@
+provider "test" {}
+
+override_data {
+  target = data.test_data_source.datasource
+  values = {
+    list_value = [
+      {
+        name = "first"
+      },
+      {
+        value = "two"
+      },
+    ]
+  }
+}
+
+run "test_override_data_list_attribute_partial_elements" {
+  command = plan
+
+  assert {
+    condition     = length(data.test_data_source.datasource.list_value) == 2
+    error_message = "Expected list_value to have 2 elements, got ${length(data.test_data_source.datasource.list_value)}"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.list_value[0].name == "first"
+    error_message = "Expected first element name to be 'first'"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.list_value[0].value != null
+    error_message = "Expected first element value to be filled in"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.list_value[1].value == "two"
+    error_message = "Expected second element value to be 'two'"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.list_value[1].name != null
+    error_message = "Expected second element name to be filled in"
+  }
+}

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

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+data "test_data_source" "datasource" {
+  id = "resource"
+}
+
+output "nested_list_value" {
+  value = data.test_data_source.datasource.nested_list_value
+}

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

@@ -0,0 +1,12 @@
+provider "test" {}
+
+override_data {
+  target = data.test_data_source.datasource
+  values = {
+    nested_list_value = "wrong type"
+  }
+}
+
+run "test_override_data_nested_list_attribute_invalid_type" {
+  command = plan
+}

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

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+data "test_data_source" "datasource" {
+  id = "resource"
+}
+
+output "nested_list_value" {
+  value = data.test_data_source.datasource.nested_list_value
+}

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

@@ -0,0 +1,19 @@
+provider "test" {}
+
+override_data {
+  target = data.test_data_source.datasource
+  values = {
+    nested_list_value = {
+      name = "shared"
+    }
+  }
+}
+
+run "test_override_data_nested_list_attribute_object" {
+  command = plan
+
+  assert {
+    condition     = length(data.test_data_source.datasource.nested_list_value) == 0
+    error_message = "Expected nested_list_value to be empty when overridden with an object"
+  }
+}

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

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+data "test_data_source" "datasource" {
+  id = "resource"
+}
+
+output "nested_list_value" {
+  value = data.test_data_source.datasource.nested_list_value
+}

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

@@ -0,0 +1,44 @@
+provider "test" {}
+
+override_data {
+  target = data.test_data_source.datasource
+  values = {
+    nested_list_value = [
+      {
+        name = "first"
+      },
+      {
+        value = "two"
+      },
+    ]
+  }
+}
+
+run "test_override_data_nested_list_attribute_partial_elements" {
+  command = plan
+
+  assert {
+    condition     = length(data.test_data_source.datasource.nested_list_value) == 2
+    error_message = "Expected nested_list_value to have 2 elements, got ${length(data.test_data_source.datasource.nested_list_value)}"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.nested_list_value[0].name == "first"
+    error_message = "Expected first element name to be 'first'"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.nested_list_value[0].value != null
+    error_message = "Expected first element value to be filled in"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.nested_list_value[1].value == "two"
+    error_message = "Expected second element value to be 'two'"
+  }
+
+  assert {
+    condition     = data.test_data_source.datasource.nested_list_value[1].name != null
+    error_message = "Expected second element name to be filled in"
+  }
+}

internal/moduletest/mocking/fill.go

@@ -17,35 +17,50 @@ import (
 // attributes and/or performing conversions to make the input value correct.
 //
 // It is similar to FillType, except it accepts attributes instead of types.
-func FillAttribute(in cty.Value, attribute *configschema.Attribute) (cty.Value, error) {
-	return fillAttribute(in, attribute, cty.Path{})
+func FillAttribute(providedMock cty.Value, attribute *configschema.Attribute) (cty.Value, error) {
+	return fillAttribute(providedMock, attribute, cty.Path{})
 }
 
-func fillAttribute(in cty.Value, attribute *configschema.Attribute, path cty.Path) (cty.Value, error) {
+func fillAttribute(providedMock cty.Value, attribute *configschema.Attribute, path cty.Path) (cty.Value, error) {
 	ty := attribute.Type
 	if attribute.NestedType != nil {
+		// For nested types, the providedMock value is interpreted in two ways:
+		// - If it's an object, it's treated as a single instance of the nested type,
+		//   and because we can't know how many instances are needed, we return an empty collection.
+		// - If it's a collection, it's treated as the whole nested type collection,
+		// and then we update each element of the collection with generated values where possible.
+		// Note: The collection type must match the attribute's nested type.
 
 		switch attribute.NestedType.Nesting {
 		case configschema.NestingSingle, configschema.NestingGroup:
-			return fillObject(in, attribute, path)
+			return fillObject(providedMock, attribute, path)
 		case configschema.NestingSet:
-			return cty.SetValEmpty(attribute.ImpliedType().ElementType()), nil
+			if providedMock.Type().IsObjectType() {
+				return cty.SetValEmpty(attribute.ImpliedType().ElementType()), nil
+			}
+			return fillIterable(providedMock, attribute, path)
 		case configschema.NestingList:
-			return fillIterable(in, attribute, path)
+			if providedMock.Type().IsObjectType() {
+				return cty.ListValEmpty(attribute.ImpliedType().ElementType()), nil
+			}
+			return fillIterable(providedMock, attribute, path)
 		case configschema.NestingMap:
-			return cty.MapValEmpty(attribute.ImpliedType().ElementType()), nil
+			if providedMock.Type().IsObjectType() {
+				return cty.MapValEmpty(attribute.ImpliedType().ElementType()), nil
+			}
+			return fillIterable(providedMock, attribute, path)
 		default:
 			panic(fmt.Errorf("unknown nesting mode: %d", attribute.NestedType.Nesting))
 		}
 	}
 
-	return fillType(in, ty, path)
+	return fillType(providedMock, ty, path)
 }
 
-func fillObject(in cty.Value, attribute *configschema.Attribute, path cty.Path) (cty.Value, error) {
-	// Then the in value must be an object.
-	if !in.Type().IsObjectType() {
-		return cty.NilVal, path.NewErrorf("incompatible types; expected object type, found %s", in.Type().FriendlyName())
+func fillObject(providedMock cty.Value, attribute *configschema.Attribute, path cty.Path) (cty.Value, error) {
+	// Then the providedMock value must be an object.
+	if !providedMock.Type().IsObjectType() {
+		return cty.NilVal, path.NewErrorf("incompatible types; expected object type, found %s", providedMock.Type().FriendlyName())
 	}
 
 	var names []string
@@ -63,8 +78,8 @@ func fillObject(in cty.Value, attribute *configschema.Attribute, path cty.Path)
 
 	children := make(map[string]cty.Value)
 	for _, name := range names {
-		if in.Type().HasAttribute(name) {
-			child, err := fillAttribute(in.GetAttr(name), attribute.NestedType.Attributes[name], path.GetAttr(name))
+		if providedMock.Type().HasAttribute(name) {
+			child, err := fillAttribute(providedMock.GetAttr(name), attribute.NestedType.Attributes[name], path.GetAttr(name))
 			if err != nil {
 				return cty.NilVal, err
 			}
@@ -76,9 +91,9 @@ func fillObject(in cty.Value, attribute *configschema.Attribute, path cty.Path)
 	return cty.ObjectVal(children), nil
 }
 
-func fillIterable(in cty.Value, attribute *configschema.Attribute, path cty.Path) (cty.Value, error) {
+func fillIterable(providedMock cty.Value, attribute *configschema.Attribute, path cty.Path) (cty.Value, error) {
 	ty := attribute.NestedType.ConfigType()
-	out, err := fillType(in, ty, path)
+	out, err := fillType(providedMock, ty, path)
 	if err != nil {
 		return cty.NilVal, err
 	}