make tofu test generate dynamic mock values (#2245)

Signed-off-by: ollevche <ollevche@gmail.com>

CHANGELOG.md

@@ -65,6 +65,7 @@ BUG FIXES:
 * Type validation for mocks and overrides are now less strict in `tofu test`. ([#2144](https://github.com/opentofu/opentofu/pull/2144))
 * Skip imports blocks logic on `tofu destroy` ([#2214](https://github.com/opentofu/opentofu/pull/2214))
 * Updated github.com/golang-jwt/jwt/v4 from 4.4.2 to 4.5.1 to make security scanners happy (no vulnerability, see [#2179](https://github.com/opentofu/opentofu/pull/2179))
+* `tofu test` is now setting `null`s for dynamic type when generating mock values. ([#2245](https://github.com/opentofu/opentofu/pull/2245))
 
 INTERNAL CHANGES:
 

internal/configs/hcl2shim/mock_value_composer.go

@@ -129,18 +129,7 @@ func (mvc MockValueComposer) composeMockValueForAttributes(schema *configschema.
 			continue
 		}
 
-		// If there's no value in defaults, we generate our own.
-		v, ok := mvc.getMockValueByType(impliedTypes[k])
-		if !ok {
-			diags = diags.Append(tfdiags.WholeContainingBody(
-				tfdiags.Error,
-				"Failed to generate mock value",
-				fmt.Sprintf("Mock value cannot be generated for dynamic type. Please specify the `%v` field explicitly in the configuration.", k),
-			))
-			continue
-		}
-
-		mockAttrs[k] = v
+		mockAttrs[k] = mvc.getMockValueByType(impliedTypes[k])
 	}
 
 	return mockAttrs, diags
@@ -289,16 +278,10 @@ func (mvc MockValueComposer) getMockValueForBlock(targetType cty.Type, configVal
 	}
 }
 
-// getMockValueByType tries to generate mock cty.Value based on provided cty.Type.
-// It will return non-ok response if it encounters dynamic type.
-func (mvc MockValueComposer) getMockValueByType(t cty.Type) (cty.Value, bool) {
+// getMockValueByType generates mock cty.Value based on provided cty.Type.
+func (mvc MockValueComposer) getMockValueByType(t cty.Type) cty.Value {
 	var v cty.Value
 
-	// just to be sure for cases when the logic below misses something
-	if t.HasDynamicTypes() {
-		return cty.Value{}, false
-	}
-
 	switch {
 	// primitives
 	case t.Equals(cty.Number):
@@ -329,24 +312,19 @@ func (mvc MockValueComposer) getMockValueByType(t cty.Type) (cty.Value, bool) {
 				continue
 			}
 
-			objV, ok := mvc.getMockValueByType(at)
-			if !ok {
-				return cty.Value{}, false
-			}
-
-			objVals[k] = objV
+			objVals[k] = mvc.getMockValueByType(at)
 		}
 
 		v = cty.ObjectVal(objVals)
 	case t.IsTupleType():
 		v = cty.EmptyTupleVal
 
-	// dynamically typed values are not supported
+	// dynamically typed values
 	default:
-		return cty.Value{}, false
+		v = cty.NullVal(cty.DynamicPseudoType)
 	}
 
-	return v, true
+	return v
 }
 
 func (mvc MockValueComposer) getMockString() string {

internal/configs/hcl2shim/mock_value_composer_test.go

@@ -528,6 +528,19 @@ func TestComposeMockValueBySchema(t *testing.T) {
 			},
 			wantError: true,
 		},
+		"dynamically-typed-values": {
+			schema: &configschema.Block{
+				Attributes: map[string]*configschema.Attribute{
+					"dynamic-field": {
+						Type:     cty.DynamicPseudoType,
+						Optional: true,
+					},
+				},
+			},
+			wantVal: cty.ObjectVal(map[string]cty.Value{
+				"dynamic-field": cty.NullVal(cty.DynamicPseudoType),
+			}),
+		},
 	}
 
 	for name, test := range tests {