EXSWCPHIPT-125 - Add tests for hipGetDeviceCount and restructure some SpawnProc tests (#2765)

catch/unit/device/hipGetDeviceCount.cc

@@ -23,6 +23,7 @@ THE SOFTWARE.
  */
 
 #include <hip_test_common.hh>
+#include <hip_test_process.hh>
 
 /**
  * hipGetDeviceCount tests
@@ -32,3 +33,25 @@ TEST_CASE("Unit_hipGetDeviceCount_NegTst") {
   // Scenario1
   REQUIRE_FALSE(hipGetDeviceCount(nullptr) == hipSuccess);
 }
+
+TEST_CASE("Unit_hipGetDeviceCount_HideDevices") {
+  int deviceCount = HipTest::getDeviceCount();
+  if (deviceCount < 2) {
+    HipTest::HIP_SKIP_TEST("This test requires more than 2 GPUs. Skipping.");
+    return;
+  }
+
+  for (int i = deviceCount; i >= 1; i--) {
+    std::string visibleStr;
+    for (int j = 0; j < i; j++) {  // Generate a string which has first i devices
+      visibleStr += std::to_string(j);
+      if (j != (i - 1)) {
+        visibleStr += ",";
+      }
+    }
+
+    hip::SpawnProc proc("getDeviceCount", true);
+    INFO("Output from process : " << proc.getOutput());
+    REQUIRE(proc.run(visibleStr) == i);
+  }
+}