v2: add full context 2048-token, repeated tokens, edge token tests

Tests/01_Model/LongContext12BTest.swift

@@ -54,6 +54,67 @@ final class LongContext12BTest: XCTestCase {
         }
     }
 
+    func testFullContext2048Tokens() throws {
+        try XCTSkipIf(model == nil, "12B model not found")
+
+        let promptLength = maxCtx
+        var tokens = [Int]()
+        for i in 0..<promptLength {
+            tokens.append(100 + (i % 1000))
+        }
+
+        var lastLogits: [Float]?
+        for (pos, tokenId) in tokens.enumerated() {
+            let logits = try model.forward(tokenId: tokenId, position: pos)
+            if pos == 0 || pos == promptLength - 1 || pos % 256 == 0 {
+                let nanCount = logits.filter { $0.isNaN }.count
+                XCTAssertEqual(nanCount, 0, "NaN at pos=\(pos)")
+                print("  pos=\(pos): logits[0..3]=\(logits.prefix(3)) NaN=\(nanCount)")
+            }
+            lastLogits = logits
+        }
+
+        var genTokens = tokens
+        for i in 0..<3 {
+            let logits = try model.forward(tokenId: genTokens.last ?? 0, position: genTokens.count - 1)
+            let nanCount = logits.filter { $0.isNaN }.count
+            XCTAssertEqual(nanCount, 0, "NaN at gen step \(i)")
+            var maxIdx = 0
+            var maxVal = logits[0]
+            for j in 1..<logits.count {
+                if logits[j] > maxVal { maxVal = logits[j]; maxIdx = j }
+            }
+            genTokens.append(maxIdx)
+            print("  gen[\(i)]: token=\(maxIdx) logit=\(maxVal)")
+        }
+    }
+
+    func testRepeatedTokensFullContext() throws {
+        try XCTSkipIf(model == nil, "12B model not found")
+
+        let promptLength = maxCtx / 2
+        for (pos, _) in (0..<promptLength).enumerated() {
+            let logits = try model.forward(tokenId: 100, position: pos)
+            if pos == 0 || pos == promptLength - 1 || pos % 256 == 0 {
+                let nanCount = logits.filter { $0.isNaN }.count
+                XCTAssertEqual(nanCount, 0, "NaN at pos=\(pos) (repeated tokens)")
+                print("  repeat pos=\(pos): logits[0..3]=\(logits.prefix(3)) NaN=\(nanCount)")
+            }
+        }
+    }
+
+    func testTokenIdBoundaries() throws {
+        try XCTSkipIf(model == nil, "12B model not found")
+
+        let edgeTokens = [0, 1, 2, model.vocabSize - 1]
+        for (pos, tokenId) in edgeTokens.enumerated() {
+            let logits = try model.forward(tokenId: tokenId, position: pos)
+            let nanCount = logits.filter { $0.isNaN }.count
+            XCTAssertEqual(nanCount, 0, "NaN for tokenId=\(tokenId)")
+            print("  edge token=\(tokenId): logits[0..3]=\(logits.prefix(3)) NaN=\(nanCount)")
+        }
+    }
+
     func testLongContext1024Tokens() throws {
         try XCTSkipIf(model == nil, "12B model not found")