[BACKPORT] fix: type defaults for variables in tests (#2244) (#2247)

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

CHANGELOG.md

@@ -5,6 +5,7 @@ BUG FIXES:
 * Changes to encryption configuration now auto-apply the migration ([#2232](https://github.com/opentofu/opentofu/pull/2232))
 * 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))
+* Variables declared in test files are now taking into account type default values. ([#2244](https://github.com/opentofu/opentofu/pull/2244))
 
 ## 1.8.6
 

internal/command/test.go

@@ -1130,6 +1130,13 @@ func parseAndApplyDefaultValues(unparsedVariables map[string]backend.UnparsedVar
 	for name, variable := range unparsedVariables {
 		value, valueDiags := variable.ParseVariableValue(configs.VariableParseLiteral)
 		diags = diags.Append(valueDiags)
+
+		// Even so the variable is declared, some of the fields could
+		// be empty and filled in via type default values.
+		if confVariable, ok := configVariables[name]; ok && confVariable.TypeDefaults != nil {
+			value.Value = confVariable.TypeDefaults.Apply(value.Value)
+		}
+
 		inputs[name] = value
 	}
 

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

@@ -3,3 +3,10 @@ variable "input" {
   type    = string
   default = "Hello, world!"
 }
+
+variable "another_input" {
+  type = object({
+    optional_string = optional(string, "type_default")
+    optional_number = optional(number, 42)
+  })
+}

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

@@ -4,4 +4,20 @@ run "applies_defaults" {
     condition     = var.input == "Hello, world!"
     error_message = "should have applied default value"
   }
+
+  variables {
+    another_input = {
+      optional_string = "Hello, world!"
+    }
+  }
+
+  assert {
+    condition     = var.another_input.optional_string == "Hello, world!"
+    error_message = "should have used custom value from test file"
+  }
+
+  assert {
+    condition     = var.another_input.optional_number == 42
+    error_message = "should have used default type value"
+  }
 }