Feat/arrow testing integration

.github/dependabot.yml

@@ -52,10 +52,3 @@ updates:
     commit-message:
       prefix: "chore: "
     open-pull-requests-limit: 10
-  - package-ecosystem: "gomod"
-    directory: "/data-generator/swift-datagen/"
-    schedule:
-      interval: "daily"
-    commit-message:
-      prefix: "chore: "
-    open-pull-requests-limit: 10

.gitignore

@@ -27,6 +27,9 @@ xcuserdata/
 # Docker
 /.docker/
 
+# Written by the file writer tests
+/Tests/ArrowTests/testfilewriter_*.arrow
+
 # Release Audit Tool
 /dev/release/apache-rat-*.jar
 /dev/release/filtered_rat.txt

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "testing"]
+	path = testing
+	url = https://github.com/apache/arrow-testing.git

Sources/Arrow/README.md

@@ -48,9 +48,4 @@ An implementation of Arrow targeting Swift.
 - Fields
 - Schema
 
-## Test data generation
 
-Test data files for the reader tests are generated by an executable built in go whose source is included in the data-generator directory.  
-```sh
-$ go build -o swift-datagen
-```

Tests/ArrowTests/ArrowTestData.swift

@@ -0,0 +1,96 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+import Foundation
+import XCTest
+
+/// Locates files in the `apache/arrow-testing` corpus.
+///
+/// The corpus is resolved from, in order:
+/// 1. The `ARROW_TEST_DATA` environment variable.
+/// 2. The `testing/data` submodule directory.
+///
+/// When neither is available the corpus is treated as absent and callers skip,
+/// so that `swift test` succeeds on a checkout where the submodule has not
+/// been initialised, and when tests run against an extracted source archive.
+enum ArrowTestData {
+    /// Root of the corpus, or `nil` when it cannot be located.
+    static var root: URL? {
+        let manager = FileManager.default
+
+        if let path = ProcessInfo.processInfo.environment["ARROW_TEST_DATA"], !path.isEmpty {
+            let url = URL(fileURLWithPath: path, isDirectory: true)
+            return manager.fileExists(atPath: url.path) ? url : nil
+        }
+
+        let fallback = repositoryRoot
+            .appendingPathComponent("testing", isDirectory: true)
+            .appendingPathComponent("data", isDirectory: true)
+        return manager.fileExists(atPath: fallback.path) ? fallback : nil
+    }
+
+    /// Absolute URL of a file inside the corpus, for example
+    /// `arrow-ipc-stream/integration/cpp-21.0.0/generated_primitive.stream`.
+    ///
+    /// Throws `XCTSkip` when the corpus is unavailable. Fails the calling test
+    /// when the corpus is present but does not contain the requested file,
+    /// which indicates a stale submodule rather than a missing corpus.
+    static func url(
+        _ relativePath: String,
+        file: StaticString = #filePath,
+        line: UInt = #line
+    ) throws -> URL {
+        guard let root else {
+            throw XCTSkip(
+                """
+                arrow-testing corpus not found. Run \
+                'git submodule update --init', or set ARROW_TEST_DATA to the \
+                data directory of an apache/arrow-testing checkout.
+                """)
+        }
+
+        let url = root.appendingPathComponent(relativePath)
+        if !FileManager.default.fileExists(atPath: url.path) {
+            XCTFail(
+                "Missing file in arrow-testing corpus: \(relativePath)",
+                file: file,
+                line: line)
+        }
+        return url
+    }
+
+    /// This file is at `<repository>/Tests/ArrowTests/ArrowTestData.swift`, so
+    /// the repository root is three levels up. `#filePath` is used rather than
+    /// `#file` because the latter can be shortened to a bare file name
+    /// depending on compiler settings.
+    private static var repositoryRoot: URL {
+        URL(fileURLWithPath: #filePath)
+            .deletingLastPathComponent()
+            .deletingLastPathComponent()
+            .deletingLastPathComponent()
+    }
+}
+
+final class ArrowTestDataTests: XCTestCase {
+    /// Verifies path resolution only. Reading and validating corpus contents
+    /// is deliberately out of scope here.
+    func testResolvesCorpusPath() throws {
+        let url = try ArrowTestData.url(
+            "arrow-ipc-stream/integration/cpp-21.0.0/generated_primitive.stream")
+        XCTAssertTrue(FileManager.default.fileExists(atPath: url.path))
+    }
+}