backport sat fuzztest from main

MODULE.bazel

@@ -9,14 +9,15 @@ OR_TOOLS_VERSION = "9.12.0"
 
 module(
     name = "or-tools",
-    repo_name = "com_google_ortools",
     version = OR_TOOLS_VERSION,
+    repo_name = "com_google_ortools",
 )
 
 bazel_dep(name = "abseil-cpp", version = "20240722.0", repo_name = "com_google_absl")
 bazel_dep(name = "bazel_skylib", version = "1.7.1")
 bazel_dep(name = "contrib_rules_jvm", version = "0.27.0")
 bazel_dep(name = "eigen", version = "3.4.0.bcr.1")
+bazel_dep(name = "fuzztest", version = "20241028.0", repo_name = "com_google_fuzztest")
 bazel_dep(name = "gazelle", version = "0.39.1", repo_name = "bazel_gazelle")
 bazel_dep(name = "glpk", version = "5.0.bcr.1")
 bazel_dep(name = "google_benchmark", version = "1.8.5", repo_name = "com_google_benchmark")
@@ -42,8 +43,8 @@ bazel_dep(name = "zlib", version = "1.3.1.bcr.3")
 git_override(
     module_name = "pybind11_abseil",
     commit = "70f8b693b3b70573ca785ef62d9f48054f45d786",
-    patches = ["//patches:pybind11_abseil.patch"],
     patch_strip = 1,
+    patches = ["//patches:pybind11_abseil.patch"],
     remote = "https://github.com/pybind/pybind11_abseil.git",
 )
 
@@ -57,14 +58,15 @@ SUPPORTED_PYTHON_VERSIONS = [
 
 DEFAULT_PYTHON = "3.11"
 
-python = use_extension("@rules_python//python/extensions:python.bzl", "python", dev_dependency=True)
+python = use_extension("@rules_python//python/extensions:python.bzl", "python", dev_dependency = True)
+
 [
-  python.toolchain(
-    ignore_root_user_error = True, # needed for CI
-    python_version = version,
-    is_default = version == DEFAULT_PYTHON,
-  )
-  for version in SUPPORTED_PYTHON_VERSIONS
+    python.toolchain(
+        ignore_root_user_error = True,  # needed for CI
+        is_default = version == DEFAULT_PYTHON,
+        python_version = version,
+    )
+    for version in SUPPORTED_PYTHON_VERSIONS
 ]
 
 pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")

ortools/base/BUILD.bazel

@@ -215,6 +215,19 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "fuzztest",
+    testonly = 1,
+    hdrs = ["fuzztest.h"],
+    deps = [
+        "@com_google_absl//absl/log:check",
+        "@com_google_fuzztest//fuzztest",
+        "@com_google_fuzztest//fuzztest:googletest_fixture_adapter",
+        "@com_google_fuzztest//fuzztest:init_fuzztest",
+        "@com_google_protobuf//:protobuf",
+    ],
+)
+
 cc_library(
     name = "status_matchers",
     hdrs = ["status_matchers.h"],

ortools/base/fuzztest.h

@@ -0,0 +1,55 @@
+// Copyright 2010-2024 Google LLC
+// Licensed 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.
+
+#ifndef OR_TOOLS_BASE_FUZZTEST_H_
+#define OR_TOOLS_BASE_FUZZTEST_H_
+
+#include <memory>
+#include <string>
+#include <string_view>
+#include <tuple>
+#include <vector>
+
+#include "fuzztest/domain.h"
+#include "fuzztest/fuzztest.h"
+#include "fuzztest/googletest_fixture_adapter.h"
+#include "fuzztest/init_fuzztest.h"
+#include "google/protobuf/message.h"
+#include "google/protobuf/text_format.h"
+#include "ortools/base/logging.h"
+
+namespace fuzztest {
+
+// Reads protos from directory and returns a vector usable by the .WithSeeds()
+// function to aid in fuzz test migrations. `is_text_format` should be true iff
+// the protos are in text format.
+template <class ProtoType>
+std::vector<std::tuple<ProtoType>> ReadFilesFromDirectory(
+    std::string_view dir) {
+  std::vector<std::tuple<ProtoType>> corpus;
+
+  for (std::tuple<std::string>& proto_tuple : ReadFilesFromDirectory(dir)) {
+    std::string text_proto = std::get<0>(proto_tuple);
+    ProtoType proto;
+    bool was_parsed =
+        google::protobuf::TextFormat::ParseFromString(text_proto, &proto);
+    if (was_parsed) {
+      corpus.push_back(std::make_tuple(proto));
+    }
+  }
+  return corpus;
+}
+
+}  // namespace fuzztest
+
+#endif  // OR_TOOLS_BASE_FUZZTEST_H_

ortools/sat/BUILD.bazel

@@ -3743,6 +3743,22 @@ cc_test(
     ],
 )
 
+cc_test(
+    name = "cp_model_solver_fuzz",
+    size = "large",
+    srcs = ["cp_model_solver_fuzz.cc"],
+    data = glob(["fuzz_testdata/*"]),
+    deps = [
+        ":cp_model_cc_proto",
+        ":cp_model_solver",
+        "//ortools/base:fuzztest",
+        "//ortools/base:path",
+        "@bazel_tools//tools/cpp/runfiles",
+        "@com_google_absl//absl/log:check",
+        "@com_google_fuzztest//fuzztest:fuzztest_gtest_main",
+    ],
+)
+
 cc_test(
     name = "flaky_models_test",
     size = "small",

ortools/sat/CMakeLists.txt

@@ -13,6 +13,7 @@
 
 file(GLOB _SRCS "*.h" "*.cc")
 list(FILTER _SRCS EXCLUDE REGEX ".*/.*_test.cc")
+list(FILTER _SRCS EXCLUDE REGEX ".*/.*_fuzz.cc")
 list(REMOVE_ITEM _SRCS
   ${CMAKE_CURRENT_SOURCE_DIR}/opb_reader.h
   ${CMAKE_CURRENT_SOURCE_DIR}/sat_cnf_reader.h

ortools/sat/cp_model_solver_fuzz.cc

@@ -0,0 +1,69 @@
+// Copyright 2010-2024 Google LLC
+// Licensed 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.
+
+#include <string>
+
+#include "absl/log/check.h"
+#include "gtest/gtest.h"  // IWYU pragma: keep
+#include "ortools/base/fuzztest.h"
+#include "ortools/base/path.h"  // IWYU pragma: keep
+#include "ortools/sat/cp_model.pb.h"
+#include "ortools/sat/cp_model_solver.h"
+#include "tools/cpp/runfiles/runfiles.h"
+
+namespace operations_research::sat {
+
+namespace {
+
+std::string GetTestDataDir() {
+  return file::JoinPathRespectAbsolute(::testing::SrcDir(),
+                                       "_main/ortools/sat/fuzz_testdata");
+}
+
+void Solve(const CpModelProto& proto) {
+  const CpSolverResponse response =
+      operations_research::sat::SolveWithParameters(proto,
+                                                    "max_time_in_seconds: 4.0");
+
+  const CpSolverResponse response_no_presolve =
+      operations_research::sat::SolveWithParameters(
+          proto, "max_time_in_seconds:4.0,cp_model_presolve:false");
+
+  CHECK_EQ(response.status() == CpSolverStatus::MODEL_INVALID,
+           response_no_presolve.status() == CpSolverStatus::MODEL_INVALID)
+      << "Model being invalid should not depend on presolve";
+
+  if (response.status() == CpSolverStatus::MODEL_INVALID) {
+    return;
+  }
+
+  if (response.status() == CpSolverStatus::UNKNOWN ||
+      response_no_presolve.status() == CpSolverStatus::UNKNOWN) {
+    return;
+  }
+
+  CHECK_EQ(response.status() == CpSolverStatus::INFEASIBLE,
+           response_no_presolve.status() == CpSolverStatus::INFEASIBLE)
+      << "Presolve should not change feasibility";
+}
+
+// Fuzzing repeats solve() 100 times, and timeout after 600s.
+// With a time limit of 4s, we should be fine.
+FUZZ_TEST(CpModelProtoFuzzer, Solve)
+    .WithDomains(/*proto:*/ fuzztest::Arbitrary<CpModelProto>())
+    .WithSeeds([]() {
+      return fuzztest::ReadFilesFromDirectory<CpModelProto>(GetTestDataDir());
+    });
+
+}  // namespace
+}  // namespace operations_research::sat

ortools/sat/fuzz_testdata/BadHintWithCore

@@ -0,0 +1,38 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 5
+}
+variables {
+  domain: 0
+  domain: 5
+}
+variables {
+  domain: 2
+  domain: 8
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    vars: 2
+    coeffs: 1
+    coeffs: 1
+    coeffs: -1
+    domain: 0
+    domain: 0
+  }
+}
+objective {
+  vars: 2
+  scaling_factor: 1
+  coeffs: 1
+}
+solution_hint {
+  vars: 0
+  vars: 1
+  values: 4
+  values: 5
+}

ortools/sat/fuzz_testdata/DualConnectedComponentsModel

@@ -0,0 +1,70 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 2
+    domain: 0
+    domain: 8
+  }
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 1
+    domain: 2
+    domain: 20
+  }
+}
+constraints {
+  linear {
+    vars: 2
+    vars: 3
+    coeffs: 1
+    coeffs: 2
+    domain: 0
+    domain: 6
+  }
+}
+constraints {
+  linear {
+    vars: 2
+    vars: 3
+    coeffs: 1
+    coeffs: 1
+    domain: 2
+    domain: 20
+  }
+}
+objective {
+  vars: -1
+  vars: -2
+  vars: -3
+  vars: -4
+  scaling_factor: -1
+  coeffs: 1
+  coeffs: 2
+  coeffs: 3
+  coeffs: 4
+}

ortools/sat/fuzz_testdata/EnumerateAllSolutions

@@ -0,0 +1,27 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 1
+  domain: 4
+}
+variables {
+  domain: 1
+  domain: 4
+}
+variables {
+  domain: 1
+  domain: 4
+}
+variables {
+  domain: 1
+  domain: 4
+}
+constraints {
+  all_diff {
+    exprs {
+      vars: [0, 1, 2, 3]
+      coeffs: [1, 1, 1, 1]
+    }
+  }
+}

ortools/sat/fuzz_testdata/EnumerateAllSolutionsBis

@@ -0,0 +1,21 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 5
+}
+variables {
+  domain: 0
+  domain: 5
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 1
+    domain: 6
+    domain: 6
+  }
+}

ortools/sat/fuzz_testdata/EnumerateAllSolutionsOfEmptyModel

@@ -0,0 +1,15 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 2
+}
+variables {
+  domain: 0
+  domain: 2
+}
+variables {
+  domain: 0
+  domain: 2
+}

ortools/sat/fuzz_testdata/HintWithCore

@@ -0,0 +1,34 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 5
+}
+variables {
+  domain: 0
+  domain: 5
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 1
+    domain: 2
+    domain: 8
+  }
+}
+objective {
+  vars: 0
+  vars: 1
+  scaling_factor: 1
+  coeffs: 1
+  coeffs: 1
+}
+solution_hint {
+  vars: 0
+  vars: 1
+  values: 2
+  values: 3
+}

ortools/sat/fuzz_testdata/InvalidProblem

@@ -0,0 +1,5 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+}

ortools/sat/fuzz_testdata/MultipleEnforcementLiteral

@@ -0,0 +1,31 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 4
+}
+variables {
+  domain: 0
+  domain: 4
+}
+constraints {
+  enforcement_literal: 0
+  enforcement_literal: 1
+  linear {
+    vars: 2
+    vars: 3
+    coeffs: 1
+    coeffs: -1
+    domain: 0
+    domain: 0
+  }
+}

ortools/sat/fuzz_testdata/NonInstantiatedVariables

@@ -0,0 +1,21 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 10
+}
+variables {
+  domain: 0
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 1
+    domain: 4
+    domain: 5
+  }
+}

ortools/sat/fuzz_testdata/ObjectiveDomainLowerBound

@@ -0,0 +1,27 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 2
+    coeffs: 1
+    domain: 10
+    domain: 10
+  }
+}
+objective {
+  vars: 1
+  coeffs: 1
+  domain: 8
+  domain: 10
+}

ortools/sat/fuzz_testdata/SimpleCumulative

@@ -0,0 +1,61 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 4
+}
+variables {
+  domain: 2
+  domain: 2
+}
+variables {
+  domain: 0
+  domain: 4
+}
+variables {
+  domain: 1
+  domain: 4
+}
+variables {
+  domain: 2
+  domain: 2
+}
+variables {
+  domain: 0
+  domain: 4
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 4
+  domain: 4
+}
+variables {
+  domain: 6
+  domain: 6
+}
+constraints {
+  interval {
+    end { vars: 2 coeffs: 1 }
+    size { vars: 2 coeffs: 1 }
+  }
+}
+constraints {
+  interval {
+    start { vars: 3 coeffs: 1 }
+    end { vars: 5 coeffs: 1 }
+    size { vars: 4 coeffs: 1 }
+  }
+}
+constraints {
+  cumulative {
+    capacity { vars: 8  coeffs: 1 }
+    intervals: 0
+    intervals: 1
+    demands: { vars: 6 coeffs: 1 }
+    demands: { vars: 7 coeffs: 1 }
+  }
+}

ortools/sat/fuzz_testdata/SimpleInterval

@@ -0,0 +1,46 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 0
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 3
+  domain: 6
+}
+constraints {
+  interval {
+    end {vars: 2 coeffs: 1 }
+    size { vars: 1 coeffs: 1 }
+  }
+}
+constraints {
+  interval {
+    start { vars: 3 coeffs: 1 }
+    end {vars: 5 coeffs: 1 }
+    size {vars: 4 coeffs: 1 }
+  }
+}
+constraints {
+  no_overlap {
+    intervals: 0
+    intervals: 1
+  }
+}

ortools/sat/fuzz_testdata/SimpleLinearExampleWithMaximize

@@ -0,0 +1,28 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: -10
+  domain: 10
+}
+variables {
+  domain: -10
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 1
+    domain: -100
+    domain: 100
+  }
+}
+objective {
+  vars: 0
+  vars: 1
+  scaling_factor: -1
+  coeffs: -1
+  coeffs: -2
+}

ortools/sat/fuzz_testdata/SimpleOptionalIntervalFeasible

@@ -0,0 +1,83 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 0
+  domain: 6
+}
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 2
+  domain: 6
+}
+variables {
+  domain: 2
+  domain: 2
+}
+variables {
+  domain: 2
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 3
+  domain: 6
+}
+constraints {
+  enforcement_literal: 0
+  interval {
+    start { vars: 1 coeffs: 1 }
+    end { vars: 3 coeffs: 1 }
+    size { vars: 2 offset: 2 }
+  }
+}
+constraints {
+  enforcement_literal: 4
+  interval {
+    start { vars: 5 coeffs: 1 }
+    end  { vars: 7 coeffs: 1 }
+    size { vars: 6 coeffs: 1 }
+  }
+}
+constraints {
+  interval {
+    start { vars: 8 coeffs: 1 }
+    end { vars: 10 coeffs: 1 }
+    size { vars: 9 coeffs: 1 }
+  }
+}
+constraints {
+  no_overlap {
+    intervals: 0
+    intervals: 1
+    intervals: 2
+  }
+}
+constraints {
+  bool_xor {
+    literals: 0
+    literals: 4
+  }
+}

ortools/sat/fuzz_testdata/SimpleOptionalIntervalInfeasible

@@ -0,0 +1,83 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 0
+  domain: 6
+}
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 2
+  domain: 6
+}
+variables {
+  domain: 2
+  domain: 2
+}
+variables {
+  domain: 2
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 6
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 3
+  domain: 6
+}
+constraints {
+  enforcement_literal: 0
+  interval {
+    start { vars: 1 coeffs: 1 }
+    end { vars: 3 coeffs: 1 }
+    size { vars: 2 coeffs: 1 }
+  }
+}
+constraints {
+  enforcement_literal: 4
+  interval {
+    start { vars: 5 coeffs: 1 }
+    end { vars: 7 coeffs: 1 }
+    size { vars: 6 coeffs: 1 }
+  }
+}
+constraints {
+  interval {
+    start { vars: 8 coeffs: 1 }
+    end { vars: 10 coeffs: 1 }
+    size { vars: 9 coeffs: 1 }
+  }
+}
+constraints {
+  no_overlap {
+    intervals: 0
+    intervals: 1
+    intervals: 2
+  }
+}
+constraints {
+  bool_and {
+    literals: 0
+    literals: 4
+  }
+}

ortools/sat/fuzz_testdata/SmallDualConnectedComponentsModel

@@ -0,0 +1,50 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 2
+    domain: 0
+    domain: 8
+  }
+}
+constraints {
+  linear {
+    vars: 2
+    vars: 3
+    coeffs: 1
+    coeffs: 2
+    domain: 0
+    domain: 6
+  }
+}
+objective {
+  vars: -1
+  vars: -2
+  vars: -3
+  vars: -4
+  scaling_factor: -1
+  coeffs: 1
+  coeffs: 2
+  coeffs: 3
+  coeffs: 4
+}

ortools/sat/fuzz_testdata/SolutionHintEnumerateTest

@@ -0,0 +1,27 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  name: "x"
+  domain: 0
+  domain: 10
+}
+variables {
+  name: "y"
+  domain: 0
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 1
+    vars: 0
+    coeffs: 1
+    coeffs: 1
+    domain: 10
+    domain: 10
+  }
+}
+solution_hint {
+  vars: 0
+  values: -1
+}

ortools/sat/fuzz_testdata/SolutionHintObjectiveTest

@@ -0,0 +1,39 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 1
+}
+objective {
+  vars: 0
+  vars: 1
+  vars: 2
+  vars: 3
+  coeffs: 1
+  coeffs: 2
+  coeffs: 3
+  coeffs: 4
+}
+solution_hint {
+  vars: 0
+  vars: 1
+  vars: 2
+  vars: 3
+  values: 1
+  values: 0
+  values: 0
+  values: 1
+}

ortools/sat/fuzz_testdata/SolutionHintOptimalObjectiveTest

@@ -0,0 +1,39 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 1
+}
+variables {
+  domain: 0
+  domain: 1
+}
+objective {
+  vars: 0
+  vars: 1
+  vars: 2
+  vars: 3
+  coeffs: -1
+  coeffs: 2
+  coeffs: 3
+  coeffs: -4
+}
+solution_hint {
+  vars: 0
+  vars: 1
+  vars: 2
+  vars: 3
+  values: 1
+  values: 0
+  values: 0
+  values: 1
+}

ortools/sat/fuzz_testdata/SolutionsAreCorrectlyPostsolvedInTheObserver

@@ -0,0 +1,19 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 1
+  domain: 4
+}
+variables {
+  domain: 1
+  domain: 1
+}
+variables {
+  domain: 3
+  domain: 3
+}
+variables {
+  domain: 1
+  domain: 4
+}

ortools/sat/fuzz_testdata/TightenedDomains

@@ -0,0 +1,27 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 0
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    vars: 2
+    coeffs: 1
+    coeffs: 2
+    coeffs: 3
+    domain: 0
+    domain: 7
+  }
+}

ortools/sat/fuzz_testdata/TightenedDomainsIfInfeasible

@@ -0,0 +1,27 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 10
+}
+variables {
+  domain: 1
+  domain: 10
+}
+variables {
+  domain: 0
+  domain: 10
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    vars: 2
+    coeffs: 1
+    coeffs: 2
+    coeffs: 3
+    domain: 80
+    domain: 87
+  }
+}

ortools/sat/fuzz_testdata/TrivialLinearTranslatedModel

@@ -0,0 +1,42 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: -10
+  domain: 10
+}
+variables {
+  domain: -10
+  domain: 10
+}
+variables {
+  domain: -4611686018427387903
+  domain: 4611686018427387903
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 1
+    domain: -4611686018427387903
+    domain: 4611686018427387903
+  }
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    vars: 2
+    coeffs: 1
+    coeffs: 2
+    coeffs: -1
+    domain: 0
+    domain: 0
+  }
+}
+objective {
+  vars: -3
+  scaling_factor: -1
+  coeffs: 1
+}

ortools/sat/fuzz_testdata/TrivialModelWithCore

@@ -0,0 +1,11 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 1
+  domain: 1
+}
+objective {
+  vars: 0
+  coeffs: 1
+}

ortools/sat/fuzz_testdata/UnsatProblem

@@ -0,0 +1,21 @@
+# proto-file: ortools/sat/cp_model.proto
+# proto-message: operations_research.sat.CpModelProto
+
+variables {
+  domain: 0
+  domain: 0
+}
+variables {
+  domain: 1
+  domain: 1
+}
+constraints {
+  linear {
+    vars: 0
+    vars: 1
+    coeffs: 1
+    coeffs: 1
+    domain: 0
+    domain: 0
+  }
+}