Merge fixes to the smoke tests

Improve smoke tests in two ways:

+ Skip smoke tests when no device is found
+ Don't use the `imbalance` strategy with CSR, which requires a device executor.

Related PR: #874

test/test_install/test_install.cpp

@@ -35,6 +35,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <chrono>
 #include <cmath>
+#include <cstdlib>
 #include <fstream>
 #include <iostream>
 #include <map>
@@ -93,8 +94,7 @@ void check_solver(std::shared_ptr<gko::Executor> exec,
                   const gko::matrix::Dense<> *b, gko::matrix::Dense<> *x)
 {
     using Mtx = gko::matrix::Csr<>;
-    auto A =
-        gko::share(Mtx::create(exec, std::make_shared<Mtx::load_balance>()));
+    auto A = gko::share(Mtx::create(exec, std::make_shared<Mtx::classical>()));
 
     auto num_iters = 20u;
     double reduction_factor = 1e-7;
@@ -117,8 +117,8 @@ void check_solver(std::shared_ptr<gko::Executor> exec,
 #if defined(HAS_HIP) || defined(HAS_CUDA)
     // If we are on a device, we need to run a reference test to compare against
     auto exec_ref = exec->get_master();
-    auto A_ref = gko::share(
-        Mtx::create(exec_ref, std::make_shared<Mtx::load_balance>()));
+    auto A_ref =
+        gko::share(Mtx::create(exec_ref, std::make_shared<Mtx::classical>()));
     A_ref->read(A_raw);
     auto solver_gen_ref =
         Solver::build()
@@ -147,13 +147,35 @@ class PolymorphicObjectTest : public gko::PolymorphicObject {};
 int main()
 {
 #if defined(HAS_CUDA)
-    auto exec = gko::CudaExecutor::create(0, gko::ReferenceExecutor::create());
+    auto extra_info = "(CUDA)";
+    using exec_type = gko::CudaExecutor;
 #elif defined(HAS_HIP)
-    auto exec = gko::HipExecutor::create(0, gko::ReferenceExecutor::create());
+    auto extra_info = "(HIP)";
+    using exec_type = gko::HipExecutor;
 #else
-    auto exec = gko::ReferenceExecutor::create();
+    auto extra_info = "(REFERENCE)";
+    using exec_type = gko::ReferenceExecutor;
 #endif
 
+    std::shared_ptr<exec_type> exec;
+    try {
+#if defined(HAS_CUDA) || defined(HAS_HIP)
+        exec = exec_type::create(0, gko::ReferenceExecutor::create());
+#else
+        exec = exec_type::create();
+#endif
+        // We also try to to synchronize to ensure we really have an available
+        // device
+        exec->synchronize();
+    } catch (gko::Error &e) {
+        // Exit gracefully to not trigger CI errors. We only skip the tests in
+        // this setting
+        std::cerr
+            << "test_install" << extra_info
+            << ": a compatible device could not be found. Skipping test.\n";
+        std::exit(0);
+    }
+
     using vec = gko::matrix::Dense<>;
 #if HAS_REFERENCE
     auto b = gko::read<vec>(std::ifstream("data/b.mtx"), exec);
@@ -329,7 +351,7 @@ int main()
     // core/matrix/csr.hpp
     {
         using Mtx = gko::matrix::Csr<>;
-        auto test = Mtx::create(exec, std::make_shared<Mtx::load_balance>());
+        auto test = Mtx::create(exec, std::make_shared<Mtx::classical>());
     }
 
     // core/matrix/dense.hpp
@@ -491,13 +513,6 @@ int main()
                 .with_criteria(std::move(time), std::move(iteration))
                 .on(exec);
     }
-#if defined(HAS_CUDA)
-    auto extra_info = "(CUDA)";
-#elif defined(HAS_HIP)
-    auto extra_info = "(HIP)";
-#else
-    auto extra_info = "(REFERENCE)";
-#endif
     std::cout << "test_install" << extra_info
               << ": the Ginkgo installation was correctly detected "
                  "and is complete."