Refactor MacroArgumentValue, reorganize files, and add unit tests (#111)

Author: graycampbell

Sources/Mocking/Models/MockedPropertyType/MockedPropertyType+AsyncSpecifier.swift renamed to Sources/Mocking/Models/MacroArguments/MockedPropertyType/MockedPropertyType+AsyncSpecifier.swift

@@ -39,7 +39,7 @@ extension MockedMacro {
                     let argument = arguments.first(where: { argument in
                         argument.label?.text == name
                     }),
-                    let value = ArgumentValue(argument: argument)
+                    let value = try? ArgumentValue(argument: argument)
                 else {
                     return `default`
                 }

Sources/Mocking/Models/MockedPropertyType/MockedPropertyType+ThrowsSpecifier.swift renamed to Sources/Mocking/Models/MacroArguments/MockedPropertyType/MockedPropertyType+ThrowsSpecifier.swift

@@ -14,5 +14,6 @@ protocol MacroArgumentValue {
     ///
     /// - Parameter argument: The argument syntax from which to parse the
     ///   macro argument value.
-    init?(argument: LabeledExprSyntax)
+    /// - Throws: An error if unable to parse the macro argument value.
+    init(argument: LabeledExprSyntax) throws
 }

Sources/Mocking/Models/MockedPropertyType/MockedPropertyType.swift renamed to Sources/Mocking/Models/MacroArguments/MockedPropertyType/MockedPropertyType.swift

@@ -0,0 +1,30 @@
+//
+//  MockCompilationCondition+ParsingError.swift
+//
+//  Copyright © 2025 Fetch.
+//
+
+import Foundation
+
+extension MockCompilationCondition {
+
+    /// A parsing error generated by ``MockCompilationCondition``.
+    enum ParsingError: CaseIterable, CustomStringConvertible, Error {
+
+        // MARK: Cases
+
+        /// An error indicating that ``MockCompilationCondition`` was unable to
+        /// parse a valid instance from the provided macro argument.
+        case unableToParseCompilationCondition
+
+        // MARK: Properties
+
+        /// The description of the error.
+        var description: String {
+            switch self {
+            case .unableToParseCompilationCondition:
+                "Unable to parse compilation condition."
+            }
+        }
+    }
+}

Sources/MockingMacros/Macros/MockedMacro/MockedMacro+MacroArguments.swift

@@ -65,7 +65,9 @@ enum MockCompilationCondition: RawRepresentable, Equatable, MacroArgumentValue {
     ///
     /// - Parameter argument: The argument syntax from which to parse a
     ///   compilation condition.
-    init?(argument: LabeledExprSyntax) {
+    /// - Throws: An error if a valid compilation condition cannot be parsed
+    ///   from the provided `argument`.
+    init(argument: LabeledExprSyntax) throws {
         let (
             memberAccessExpression,
             arguments
@@ -103,7 +105,7 @@ enum MockCompilationCondition: RawRepresentable, Equatable, MacroArgumentValue {
         }
 
         guard let memberAccessExpression else {
-            return nil
+            throw ParsingError.unableToParseCompilationCondition
         }
 
         let declarationNameTokenKind = memberAccessExpression.declName.baseName.tokenKind
@@ -125,7 +127,7 @@ enum MockCompilationCondition: RawRepresentable, Equatable, MacroArgumentValue {
         {
             self = .custom(condition)
         } else {
-            return nil
+            throw ParsingError.unableToParseCompilationCondition
         }
     }
 }

Sources/MockingMacros/Models/MacroArguments/MacroArgumentValue.swift

@@ -0,0 +1,30 @@
+//
+//  MockSendableConformance+ParsingError.swift
+//
+//  Copyright © 2025 Fetch.
+//
+
+import Foundation
+
+extension MockSendableConformance {
+
+    /// A parsing error generated by ``MockSendableConformance``.
+    enum ParsingError: CaseIterable, CustomStringConvertible, Error {
+
+        // MARK: Cases
+
+        /// An error indicating that ``MockSendableConformance`` was unable to
+        /// parse a valid instance from the provided macro argument.
+        case unableToParseSendableConformance
+
+        // MARK: Properties
+
+        /// The description of the error.
+        var description: String {
+            switch self {
+            case .unableToParseSendableConformance:
+                "Unable to parse Sendable conformance."
+            }
+        }
+    }
+}

Sources/MockingMacros/Models/MacroArguments/MockCompilationCondition/MockCompilationCondition+ParsingError.swift

@@ -21,16 +21,17 @@ enum MockSendableConformance: String, MacroArgumentValue {
     ///
     /// - Parameter argument: The argument syntax from which to parse a
     ///   `Sendable` conformance.
-    init?(argument: LabeledExprSyntax) {
+    init(argument: LabeledExprSyntax) throws {
         guard
             let memberAccessExpression = argument.expression.as(
                 MemberAccessExprSyntax.self
             ),
-            let identifier = memberAccessExpression.declName.baseName.identifier
+            let identifier = memberAccessExpression.declName.baseName.identifier,
+            let sendableConformance = MockSendableConformance(rawValue: identifier.name)
         else {
-            return nil
+            throw ParsingError.unableToParseSendableConformance
         }
 
-        self.init(rawValue: identifier.name)
+        self = sendableConformance
     }
 }