[TravisCI] Workaround slow unit test execution for Debug builds.

Unit tests execute very slowly in Debug (i.e. unoptimized) builds.  This
causes TravisCI to terminate the job due to no console output being
seen.

To workaround this for the debug builds the tests are just compiled
but not executed. To implement this the `RUN_UNIT_TESTS` environment
variable now can take on the values `BUILD_ONLY`, `BUILD_AND_RUN`,
and `SKIP` rather than `0` or `1`.

.travis.yml

@@ -22,10 +22,17 @@ env:
     # 64-bit Clang 3.9 RelWithDebInfo
     - LINUX_BASE=ubuntu_16.04 C_COMPILER=/usr/bin/clang-3.9 CXX_COMPILER=/usr/bin/clang++-3.9 TARGET_ARCH=x86_64 Z3_BUILD_TYPE=RelWithDebInfo
 
+    # Debug builds
+    #
+    # Note the unit tests for the debug builds are compiled but **not**
+    # executed. This is because the debug build of unit tests takes a large
+    # amount of time to execute compared to the optimized builds. The hope is
+    # that just running the optimized unit tests is sufficient.
+    #
     # 64-bit GCC 5.4 Debug
-    - LINUX_BASE=ubuntu_16.04 C_COMPILER=/usr/bin/gcc-5 CXX_COMPILER=/usr/bin/g++-5 TARGET_ARCH=x86_64 Z3_BUILD_TYPE=Debug
+    - LINUX_BASE=ubuntu_16.04 C_COMPILER=/usr/bin/gcc-5 CXX_COMPILER=/usr/bin/g++-5 TARGET_ARCH=x86_64 Z3_BUILD_TYPE=Debug RUN_UNIT_TESTS=BUILD_ONLY
     # 64-bit Clang Debug
-    - LINUX_BASE=ubuntu_16.04 C_COMPILER=/usr/bin/clang-3.9 CXX_COMPILER=/usr/bin/clang++-3.9 TARGET_ARCH=x86_64 Z3_BUILD_TYPE=Debug
+    - LINUX_BASE=ubuntu_16.04 C_COMPILER=/usr/bin/clang-3.9 CXX_COMPILER=/usr/bin/clang++-3.9 TARGET_ARCH=x86_64 Z3_BUILD_TYPE=Debug RUN_UNIT_TESTS=BUILD_ONLY
 
     # 32-bit GCC 5.4 RelWithDebInfo
     - LINUX_BASE=ubuntu32_16.04 C_COMPILER=/usr/bin/gcc-5 CXX_COMPILER=/usr/bin/g++-5 TARGET_ARCH=i686 Z3_BUILD_TYPE=RelWithDebInfo

contrib/ci/README.md

@@ -31,7 +31,7 @@ the future.
 * `NO_SUPPRESS_OUTPUT` - Don't suppress output of some commands (`0` or `1`)
 * `PYTHON_BINDINGS` - Build and test Python API bindings (`0` or `1`)
 * `RUN_SYSTEM_TESTS` - Run system tests (`0` or `1`)
-* `RUN_UNIT_TESTS` - Run unit tests (`0` or `1`)
+* `RUN_UNIT_TESTS` - Run unit tests (`BUILD_ONLY` or `BUILD_AND_RUN` or `SKIP`)
 * `TARGET_ARCH` - Target architecture (`x86_64` or `i686`)
 * `TEST_INSTALL` - Test running `install` target (`0` or `1`)
 * `UBSAN_BUILD` - Do [UndefinedBehaviourSanitizer](https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html) build (`0` or `1`)

contrib/ci/scripts/ci_defaults.sh

@@ -10,7 +10,7 @@ export JAVA_BINDINGS="${JAVA_BINDINGS:-1}"
 export NO_SUPPRESS_OUTPUT="${NO_SUPPRESS_OUTPUT:-0}"
 export PYTHON_BINDINGS="${PYTHON_BINDINGS:-1}"
 export RUN_SYSTEM_TESTS="${RUN_SYSTEM_TESTS:-1}"
-export RUN_UNIT_TESTS="${RUN_UNIT_TESTS:-1}"
+export RUN_UNIT_TESTS="${RUN_UNIT_TESTS:-BUILD_AND_RUN}"
 export TARGET_ARCH="${TARGET_ARCH:-x86_64}"
 export TEST_INSTALL="${TEST_INSTALL:-1}"
 export UBSAN_BUILD="${UBSAN_BUILD:-0}"

contrib/ci/scripts/test_z3_unit_tests_cmake.sh

@@ -10,17 +10,35 @@ set -o pipefail
 : ${Z3_BUILD_DIR?"Z3_BUILD_DIR must be specified"}
 : ${RUN_UNIT_TESTS?"RUN_UNIT_TESTS must be specified"}
 
-if [ "X${RUN_UNIT_TESTS}" != "X1" ]; then
-  echo "Skipping unit tests"
-  exit 0
-fi
-
 # Set CMake generator args
 source ${SCRIPT_DIR}/set_generator_args.sh
 
 cd "${Z3_BUILD_DIR}"
 
-# Build and run internal tests
-cmake --build $(pwd) --target test-z3 "${GENERATOR_ARGS[@]}"
-# Run all tests that don't require arguments
-run_quiet ./test-z3 /a
+function build_unit_tests() {
+  # Build internal tests
+  cmake --build $(pwd) --target test-z3 "${GENERATOR_ARGS[@]}"
+}
+
+function run_unit_tests() {
+  # Run all tests that don't require arguments
+  run_quiet ./test-z3 /a
+}
+
+case "${RUN_UNIT_TESTS}" in
+  BUILD_AND_RUN)
+    build_unit_tests
+    run_unit_tests
+  ;;
+  BUILD_ONLY)
+    build_unit_tests
+  ;;
+  SKIP)
+    echo "RUN_UNIT_TESTS set to \"${RUN_UNIT_TESTS}\" so skipping build and run"
+    exit 0
+  ;;
+  *)
+    echo "Error: RUN_UNIT_TESTS set to unhandled value \"${RUN_UNIT_TESTS}\""
+    exit 1
+  ;;
+esac