test: strengthen startup oracles and reject empty selections

.github/scripts/test_ci_workflow_contracts.py

@@ -17,6 +17,26 @@
 
 
 class WorkflowContractsTest(unittest.TestCase):
+    def test_ctest_invocations_reject_empty_selections(self):
+        workflow = (ROOT / ".github/workflows/test.yaml").read_text()
+        commands = re.findall(r"\bctest\s+[^\n]+", workflow)
+        self.assertTrue(commands)
+        for command in commands:
+            with self.subTest(command=command):
+                self.assertEqual(
+                    re.findall(r"--no-tests(?:=|\s+)(\w+)", command), ["error"]
+                )
+
+        with tempfile.TemporaryDirectory() as directory:
+            result = subprocess.run(
+                ["ctest", "--test-dir", directory, "--no-tests=error"],
+                capture_output=True,
+                text=True,
+                check=False,
+            )
+            self.assertNotEqual(result.returncode, 0)
+            self.assertIn("No tests were found", result.stdout + result.stderr)
+
     def test_wheels_preserve_abi_coverage_and_release_gates(self):
         workflow = (ROOT / ".github/workflows/release.yml").read_text()
         config = tomllib.loads((ROOT / "pyproject.toml").read_text())

.github/workflows/test.yaml

@@ -152,14 +152,14 @@ jobs:
             -DCMAKE_BUILD_TYPE=Release \
             -DCMAKE_PREFIX_PATH="$PWD/rabitqlib-native-install"
           cmake --build build-native-consumer
-          ctest --test-dir build-native-consumer --output-on-failure
+          ctest --test-dir build-native-consumer --output-on-failure --no-tests=error
       - name: Test add_subdirectory isolation
         run: |
           cmake -S tests/consumer -B build-source-consumer -G Ninja \
             -DCMAKE_BUILD_TYPE=Release -DRABITQ_SOURCE_DIR="$PWD" \
             -DRABITQ_ENABLE_NATIVE_OPTIMIZATION=ON
           cmake --build build-source-consumer
-          ctest --test-dir build-source-consumer --output-on-failure
+          ctest --test-dir build-source-consumer --output-on-failure --no-tests=error
 
   clang:
     name: Clang 23 (OpenMP ${{ matrix.openmp }})
@@ -256,14 +256,14 @@ jobs:
       - name: Build
         run: cmake --build build-windows --config Release --parallel 2
       - name: Test
-        run: ctest --test-dir build-windows -C Release --output-on-failure
+        run: ctest --test-dir build-windows -C Release --output-on-failure --no-tests=error
       - name: Test installed CMake package and header requirements
         run: |
           cmake --install build-windows --config Release --prefix "$PWD/rabitqlib-install"
           cmake -S tests/consumer -B build-consumer -G "Visual Studio 18 2026" -A x64 `
             "-DCMAKE_PREFIX_PATH=$PWD/rabitqlib-install"
           cmake --build build-consumer --config Release --parallel 2
-          ctest --test-dir build-consumer -C Release --output-on-failure
+          ctest --test-dir build-consumer -C Release --output-on-failure --no-tests=error
 
   sanitizers:
     needs: changes
@@ -305,7 +305,7 @@ jobs:
             -DCMAKE_PREFIX_PATH="$PWD/rabitqlib-sanitized-install" \
             -DRABITQ_EXPECT_SANITIZERS=ON
           cmake --build build-sanitized-consumer
-          ctest --test-dir build-sanitized-consumer --output-on-failure
+          ctest --test-dir build-sanitized-consumer --output-on-failure --no-tests=error
 
   downstream-consumer:
     needs: changes
@@ -330,7 +330,7 @@ jobs:
             -DCMAKE_INSTALL_PREFIX="$PWD/rabitqlib-install"
           cmake --build build-install
       - name: Test portable Release build
-        run: ctest --test-dir build-install --output-on-failure
+        run: ctest --test-dir build-install --output-on-failure --no-tests=error
       - name: Download pinned Intel SDE
         run: |
           curl --fail --location --retry 3 --max-time 120 \
@@ -365,7 +365,7 @@ jobs:
             -DCMAKE_PREFIX_PATH="$PWD/rabitqlib-install"
           cmake --build build-consumer
       - name: Test downstream consumer
-        run: ctest --test-dir build-consumer --output-on-failure
+        run: ctest --test-dir build-consumer --output-on-failure --no-tests=error
 
   core-consumer:
     name: Core and FastScan consumers (${{ matrix.os }}, OpenMP ${{ matrix.openmp }}${{ matrix.component && format(', {0}', matrix.component) || '' }})
@@ -483,14 +483,14 @@ jobs:
       - name: Build and run C++ tests
         run: |
           cmake --build build --parallel 2
-          ctest --test-dir build --output-on-failure
+          ctest --test-dir build --output-on-failure --no-tests=error
       - name: Test installed CMake package
         run: |
           cmake --install build --prefix "$RUNNER_TEMP/rabitq-install"
           cmake -S tests/consumer -B build-consumer -G Ninja \
             -DCMAKE_PREFIX_PATH="$RUNNER_TEMP/rabitq-install"
           cmake --build build-consumer --parallel 2
-          ctest --test-dir build-consumer --output-on-failure
+          ctest --test-dir build-consumer --output-on-failure --no-tests=error
 
   macos-arm64:
     name: Native Apple Silicon C++
@@ -515,12 +515,12 @@ jobs:
       - name: Build and run C++ reference and index tests
         run: |
           cmake --build build --parallel 3
-          ctest --test-dir build --output-on-failure
+          ctest --test-dir build --output-on-failure --no-tests=error
       - name: Test installed CMake package
         run: |
           cmake --install build --prefix "$RUNNER_TEMP/rabitq-install"
           cmake -S tests/consumer -B build-consumer \
             -DCMAKE_PREFIX_PATH="$RUNNER_TEMP/rabitq-install" \
             -DOpenMP_ROOT="$(brew --prefix libomp)"
           cmake --build build-consumer --parallel 3
-          ctest --test-dir build-consumer --output-on-failure
+          ctest --test-dir build-consumer --output-on-failure --no-tests=error

tests/core_consumer/core_static_init.cpp

@@ -14,13 +14,22 @@ namespace {
 const bool kBeforeMain = [] {
     namespace api = rabitqlib::quant::v1;
     std::array<float, 64> input{}, rotated{}, query{};
+    double input_norm_sqr = 0;
     for (size_t i = 0; i < input.size(); ++i) {
         input[i] = static_cast<float>(i % 11) - 5.0F;
+        input_norm_sqr += static_cast<double>(input[i]) * input[i];
     }
     rabitqlib::rotator_impl::FhtKacRotator rotator(64, 64, 42);
     rotator.rotate(input.data(), rotated.data());
-    query = rotated;
+    // A half-length collinear query gives known, nonzero results for both metrics.
+    for (size_t i = 0; i < query.size(); ++i) {
+        query[i] = rotated[i] * 0.5F;
+    }
     for (const auto metric : {rabitqlib::METRIC_L2, rabitqlib::METRIC_IP}) {
+        const double expected = metric == rabitqlib::METRIC_L2 ? 0.25 * input_norm_sqr
+                                                               : 1 - 0.5 * input_norm_sqr;
+        // Reference the original coordinates, allowing float rotation/scoring roundoff.
+        const double tolerance = 2e-5 * (1 + input_norm_sqr);
         for (size_t bits = 1; bits <= 9; ++bits) {
             const api::Parameters params{64, bits, metric};
             const auto req = api::requirements(params, api::CodeLayout::SplitPacked);
@@ -46,7 +55,7 @@ const bool kBeforeMain = [] {
                  {extra.data(), extra.size()}},
                 factors
             );
-            if (!std::isfinite(distance)) {
+            if (!std::isfinite(distance) || std::abs(distance - expected) > tolerance) {
                 return false;
             }
         }

tests/dispatch/modules_static_init.cpp

@@ -1,4 +1,5 @@
 #include <array>
+#include <cstddef>
 #include <cstdint>
 
 #include "rabitqlib/fastscan/fastscan.hpp"
@@ -10,18 +11,44 @@
 namespace {
 const bool kBeforeMain = [] {
     std::array<float, 64> query{};
+    for (size_t i = 0; i < query.size(); ++i) {
+        query[i] = static_cast<float>(i % 4 + 1);
+    }
     std::array<float, 256> lut{};
+    lut.fill(-1.0F);
     rabitqlib::fastscan::pack_lut(64, query.data(), lut.data());
+    for (size_t i = 0; i < lut.size(); ++i) {
+        // The first coordinate occupies the high bit of each four-bit code.
+        float expected = 0;
+        for (size_t bit = 0; bit < 4; ++bit) {
+            if ((i % 16) & (size_t{1} << bit)) {
+                expected += static_cast<float>(4 - bit);
+            }
+        }
+        if (lut[i] != expected) {
+            return false;
+        }
+    }
     std::array<uint16_t, 256> integer_lut{};
+    // Equal nonzero bytes make the packed result independent of the HACC layout.
+    integer_lut.fill(0x0101);
     std::array<uint8_t, 512> packed_lut{};
+    packed_lut.fill(0xAB);
     std::array<uint8_t, 256> codes{};
     std::array<int32_t, 32> scores{};
+    scores.fill(-1);
     rabitqlib::fastscan::transfer_lut_hacc(integer_lut.data(), 64, packed_lut.data());
+    for (const auto value : packed_lut) {
+        if (value != 1) {
+            return false;
+        }
+    }
     rabitqlib::fastscan::accumulate_hacc(
         codes.data(), packed_lut.data(), scores.data(), 64
     );
     for (const auto score : scores) {
-        if (score != 0) {
+        // Sixteen four-coordinate tables, each contributing 0x0101.
+        if (score != 16 * 0x0101) {
             return false;
         }
     }