testing: Implement Macros For Cli Testing

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Tests/Support.swift

@@ -0,0 +1,104 @@
+// p4rse, Copyright 2026, Will Hawkins
+//
+// This file is part of p4rse.
+//
+// This file is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import Foundation
+import Testing
+
+typealias Accessor =
+  @convention(c) (
+    _ outValue: UnsafeMutableRawPointer,
+    _ type: UnsafeRawPointer,
+    _ hint: UnsafeRawPointer?,
+    _ reserved: UInt
+  ) -> CBool
+
+typealias TestContentRecord = (
+  kind: UInt32,
+  reserved1: UInt32,
+  accessor: Accessor?,
+  context: UInt,
+  reserved2: UInt
+)
+
+func findPathEnv() -> [URL]? {
+  for (key, value) in ProcessInfo().environment {
+    if key == "PATH" {
+      return value.split(separator: ":").map { URL(filePath: "\($0)") }
+    }
+  }
+
+  return .none
+}
+
+func findInPath(_ what: String) -> URL? {
+  guard let bin_paths = findPathEnv() else {
+    return .none
+  }
+
+  let fm = FileManager()
+  for bin_path in bin_paths {
+    let sought = bin_path.appending(path: what)
+    if fm.fileExists(atPath: sought.path) {
+      return sought
+    }
+  }
+
+  return .none
+}
+
+func swiftPath() -> URL? {
+  return findInPath("swift")
+}
+
+func swiftRun(withArgs args: [String]) throws -> String? {
+  let path = swiftPath()!
+  let child = Process()
+  let so = Pipe()
+  let se = Pipe()
+
+  child.standardOutput = so
+  child.executableURL = path
+  child.arguments =
+    [
+      "run",
+      "--ignore-lock" /* --ignore-lock needs to be early because it is a "location option". */,
+      "--skip-build",
+    ] + args
+
+  try! child.run()
+
+  let output =
+    switch child.standardOutput {
+    case let so as Pipe:
+      String(data: try! so.fileHandleForReading.readToEnd()!, encoding: String.Encoding.ascii)
+    default: Optional<String>.none
+    }
+  return output
+}
+
+func swiftCliTestRunner(_ arg_gen: () -> [String], _ expected: String) async throws {
+  let args = arg_gen()
+
+  let run_output = try! swiftRun(withArgs: args)
+
+  #expect(run_output == expected)
+}
+
+
+
+@attached(peer) public macro CliTest() =
+  #externalMacro(module: "Macros", type: "CliTestDeclarationMacro")

Tests/p4rseTests/CliTests/Cli.swift

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+// p4rse, Copyright 2026, Will Hawkins
+//
+// This file is part of p4rse.
+//
+// This file is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import Foundation
+import Testing
+
+/// Success
+/// 
+@CliTest()
+func simple_cli_test() -> [String] {
+    return ["p4ce", "--plain", "compile", "simple.p4", "-I", "TestData/Sources/"]
+}