diff --git a/test/simulator/hei_sim_main.cpp b/test/simulator/hei_sim_main.cpp
deleted file mode 100644
index c2bb24e..0000000
--- a/test/simulator/hei_sim_main.cpp
+++ /dev/null
@@ -1,25 +0,0 @@
-#include <hei_main.hpp>
-
-int main()
-{
-    using namespace libhei;
-
-    void* buffer     = nullptr;
-    size_t sz_buffer = 0;
-
-    initialize(buffer, sz_buffer);
-
-    Chip c1, c2;
-
-    std::vector<Chip> chipList;
-    chipList.push_back(c1);
-    chipList.push_back(c2);
-
-    IsolationData isoData;
-
-    isolate(chipList, isoData);
-
-    uninitialize();
-
-    return 0;
-}
diff --git a/test/simulator/hei_sim_user_interface.cpp b/test/simulator/hei_sim_user_interface.cpp
deleted file mode 100644
index f1025c9..0000000
--- a/test/simulator/hei_sim_user_interface.cpp
+++ /dev/null
@@ -1,57 +0,0 @@
-#include <hei_includes.hpp>
-#include <hei_user_interface.hpp>
-
-namespace libhei
-{
-
-//------------------------------------------------------------------------------
-
-ReturnCode registerRead(void* i_chip, void* o_buffer, size_t& io_bufSize,
-                        uint64_t i_regType, uint64_t i_address)
-{
-    ReturnCode rc;
-
-    HEI_ASSERT(nullptr != i_chip);
-    HEI_ASSERT(nullptr != o_buffer);
-    HEI_ASSERT(0 != io_bufSize);
-
-    switch (i_regType)
-    {
-        default:
-            rc = RC_REG_ACCESS_FAILURE;
-            HEI_ERR("registerRead(%p,%p,%lx,%lx,%lx)", i_chip, o_buffer,
-                    io_bufSize, i_regType, i_address);
-    }
-
-    return rc;
-}
-
-//------------------------------------------------------------------------------
-
-#ifndef __HEI_READ_ONLY
-
-ReturnCode registerWrite(void* i_chip, void* i_buffer, size_t& io_bufSize,
-                         uint64_t i_regType, uint64_t i_address)
-{
-    ReturnCode rc;
-
-    HEI_ASSERT(nullptr != i_chip);
-    HEI_ASSERT(nullptr != i_buffer);
-    HEI_ASSERT(0 != io_bufSize);
-
-    switch (i_regType)
-    {
-        default:
-            rc = RC_REG_ACCESS_FAILURE;
-            HEI_ERR("registerWrite(%p,%p,%lx,%lx,%lx)", i_chip, i_buffer,
-                    io_bufSize, i_regType, i_address);
-    }
-
-    return rc;
-}
-
-#endif
-
-//------------------------------------------------------------------------------
-
-} // end namespace libhei
diff --git a/test/simulator/meson.build b/test/simulator/meson.build
index 5b8a228..88de4b8 100644
--- a/test/simulator/meson.build
+++ b/test/simulator/meson.build
@@ -1,14 +1,27 @@
-sim_sources = [
-    'hei_sim_main.cpp',
-    'hei_sim_user_interface.cpp',
+# Simulator sources
+sim_src = [
+    'simulator.cpp',
+    'user_interface.cpp',
+]
+
+# Isolator sources
+iso_src = [
     '../../src/isolator/hei_isolator.cpp',
     '../../src/isolator/hei_isolation_node.cpp',
     '../../src/register/hei_hardware_register.cpp',
     '../../src/util/hei_bit_string.cpp',
 ]
 
-sim = executable('simulator', sim_sources, \
-                    include_directories: incdir)
+# Test cases
+test_src = [
+    'sample_test_case.cpp',
+]
 
-test('simulator', sim)
+gtest = dependency('gtest', main : true, required : false, method : 'system')
+
+if gtest.found()
+    test('simulator', \
+         executable('simulator', sim_src, iso_src, test_src, \
+                    dependencies : gtest, include_directories: incdir))
+endif
 
diff --git a/test/simulator/sample_test_case.cpp b/test/simulator/sample_test_case.cpp
new file mode 100644
index 0000000..1a44a32
--- /dev/null
+++ b/test/simulator/sample_test_case.cpp
@@ -0,0 +1,18 @@
+#include "simulator.hpp"
+
+START_TEST_CASE(SampleTestSet1)
+
+CHIP(proc0, 0xdeadbeef)
+
+START_ITERATION
+
+REG_IDSCOM(proc0, 0x80000000FF000000, 0x8000) // parent FIR bit 48
+
+REG_SCOM(proc0, 0x00FF0000, 0x8800000000000000) // child FIR bits 0 and 4
+
+EXP_SIG(proc0, 0x2222, 0, 0, CHECKSTOP)
+EXP_SIG(proc0, 0x2222, 0, 4, CHECKSTOP)
+
+END_ITERATION
+
+END_TEST_CASE
diff --git a/test/simulator/simulator.cpp b/test/simulator/simulator.cpp
new file mode 100644
index 0000000..0c307c2
--- /dev/null
+++ b/test/simulator/simulator.cpp
@@ -0,0 +1,54 @@
+#include "simulator.hpp"
+
+using namespace libhei;
+
+//------------------------------------------------------------------------------
+
+void SimulatorData::addChip(const Chip& i_chip)
+{
+    // First check if this entry already exists.
+    auto itr = std::find(iv_chipList.begin(), iv_chipList.end(), i_chip);
+    ASSERT_EQ(iv_chipList.end(), itr);
+
+    // Add the new entry.
+    iv_chipList.push_back(i_chip);
+
+    // TODO: Find the chip data file based on the chip type from i_chip. Read
+    //       that file in to memory and call initialize.
+    void* buffer     = nullptr;
+    size_t sz_buffer = 0;
+
+    ReturnCode rc = initialize(buffer, sz_buffer);
+    ASSERT_TRUE(RC_SUCCESS == rc || RC_CHIP_DATA_INITIALIZED == rc);
+}
+
+//------------------------------------------------------------------------------
+
+void SimulatorData::endIteration()
+{
+    // Start by calling libhei::isolate().
+    IsolationData isoData{};
+    ReturnCode rc = isolate(iv_chipList, isoData);
+
+    // It is possible that even in a failure scenario the information in the
+    // returned IsolationData would be useful.
+    // TODO: Figure out where to put the data.
+
+    // Verify if isolation completed successfully.
+    ASSERT_TRUE(RC_SUCCESS == rc);
+
+    // Get the list of signatures found in isolation.
+    std::vector<Signature> givenSigList = isoData.getSignatureList();
+
+    // Verify the expected list and given list are the same.
+    ASSERT_EQ(iv_expSigList.size(), givenSigList.size());
+
+    std::sort(iv_expSigList.begin(), iv_expSigList.end());
+    std::sort(givenSigList.begin(), givenSigList.end());
+
+    ASSERT_TRUE(std::equal(givenSigList.begin(), givenSigList.end(),
+                           iv_expSigList.begin()));
+
+    // The iteration is complete so we can flush the data.
+    flushIterationData();
+}
diff --git a/test/simulator/simulator.hpp b/test/simulator/simulator.hpp
new file mode 100644
index 0000000..9fe5c2b
--- /dev/null
+++ b/test/simulator/simulator.hpp
@@ -0,0 +1,230 @@
+#pragma once
+
+#include <hei_main.hpp>
+
+#include "gtest/gtest.h"
+
+namespace libhei
+{
+
+/**
+ * @brief Contains simulated chip objects and register contents used during
+ *        isolation. Also contains the expected signatures to compare after
+ *        isolation.
+ */
+class SimulatorData
+{
+  private: // This class cannot be instantiated. Use getSingleton() instead.
+    /** @brief Default constructor. */
+    SimulatorData() = default;
+
+    /** @brief Destructor. */
+    ~SimulatorData() = default;
+
+    /** @brief Copy constructor. */
+    SimulatorData(const SimulatorData&) = delete;
+
+    /** @brief Assignment operator. */
+    SimulatorData& operator=(const SimulatorData&) = delete;
+
+  public:
+    /** @brief Provides access to a singleton instance of this object. */
+    static SimulatorData& getSingleton()
+    {
+        static SimulatorData theSimData{};
+        return theSimData;
+    }
+
+  private:
+    /** The list of configured chips used throughout a test case. */
+    std::vector<Chip> iv_chipList;
+
+    /** The contents of all the SCOM registers used for an iteration of
+     *  isolation. */
+    std::map<Chip, std::map<uint32_t, uint64_t>> iv_scomRegData;
+
+    /** The contents of all the Indirect SCOM registers used for an iteration of
+     *  isolation. */
+    std::map<Chip, std::map<uint64_t, uint64_t>> iv_idScomRegData;
+
+    /** The list of expected signatures during an iteration of isolation. */
+    std::vector<Signature> iv_expSigList;
+
+  public:
+    /**
+     * @brief Adds a chip to the list of configured chips. Also, calls the main
+     *        initialize() API which will initialize the isolator with the Chip
+     *        Data File associated with this chip.
+     */
+    void addChip(const Chip& i_chip);
+
+    /** @brief Adds a SCOM register to iv_scomRegData. */
+    void addScomReg(const Chip& i_chip, uint32_t i_address, uint64_t i_value)
+    {
+        // First check if this entry already exists.
+        auto chip_itr = iv_scomRegData.find(i_chip);
+        if (iv_scomRegData.end() != chip_itr)
+        {
+            auto addr_itr = chip_itr->second.find(i_address);
+            ASSERT_EQ(chip_itr->second.end(), addr_itr);
+        }
+
+        // Add the new entry.
+        iv_scomRegData[i_chip][i_address] = i_value;
+    }
+
+    /** @brief Adds a SCOM register to iv_idScomRegData. */
+    void addIdScomReg(const Chip& i_chip, uint64_t i_address, uint64_t i_value)
+    {
+        // First check if this entry already exists.
+        auto chip_itr = iv_idScomRegData.find(i_chip);
+        if (iv_idScomRegData.end() != chip_itr)
+        {
+            auto addr_itr = chip_itr->second.find(i_address);
+            ASSERT_EQ(chip_itr->second.end(), addr_itr);
+        }
+
+        // Add the new entry.
+        iv_idScomRegData[i_chip][i_address] = i_value;
+    }
+
+    /** @brief Adds a Signature to iv_expSigList. */
+    void addSignature(const Signature& i_signature)
+    {
+        // First check if this entry already exists.
+        auto itr =
+            std::find(iv_expSigList.begin(), iv_expSigList.end(), i_signature);
+        ASSERT_EQ(iv_expSigList.end(), itr);
+
+        // Add the new entry.
+        iv_expSigList.push_back(i_signature);
+    }
+
+    /**
+     * @brief Flushes register and expected signature lists used for a single
+     *        isolation.
+     */
+    void flushIterationData()
+    {
+        iv_scomRegData.clear();
+        iv_idScomRegData.clear();
+        iv_expSigList.clear();
+    }
+
+    /** @brief Flushes all simulation data. */
+    void flushAll()
+    {
+        flushIterationData();
+        iv_chipList.clear();
+    }
+
+    /**
+     * @brief After an iteration is set up with registers and expected
+     *        signatures, this is called to run the simulation and verify the
+     *        expected signatures.
+     */
+    void endIteration();
+};
+
+} // end namespace libhei
+
+//------------------------------------------------------------------------------
+
+// clang-format off
+
+// The following macros can be used to simplify commonly used function for
+// simulation test cases. At the core of each test case is a Google Test (i.e.
+// gtest), which will do most of the error checking. Just like in gtest, a test
+// case file can contain more than one test. Also, remember that this is all C++
+// code. While it not likely to be used much, you can combine these macros with
+// C++ code to do more advanced test cases. For example, you can put the
+// iteration macros in a loop to walk through each bit of a register.
+
+/**
+ * This is the beginning of a test case. The NAME parameter must be valid C++
+ * identifier and must not contain any underscores (per gtest requirement). To
+ * end the test case use END_TEST_CASE. All contents of the test case must be
+ * contain in between these two macros.
+ */
+#define START_TEST_CASE(NAME)                                                  \
+    TEST(Simulator, NAME)                                                      \
+    {                                                                          \
+        libhei::SimulatorData& simData =                                       \
+            libhei::SimulatorData::getSingleton();                             \
+        simData.flushAll();
+
+/**
+ * Use this to configure a chip object for the test case. There should be an
+ * instance of this macro for each chip required for the test case. Note that
+ * this will also call libhei::initialize() for each new chip type. The CHIP
+ * parameter must be valid C++ identifier because it will be used as the name of
+ * the chip variable. This same identifier will be re-used in several other
+ * macros.
+ */
+#define CHIP(CHIP, TYPE)                                                       \
+    libhei::Chip CHIP{#CHIP, static_cast<libhei::ChipType_t>(TYPE)};           \
+    simData.addChip(CHIP);
+
+/**
+ * Once all of the chips have been configured, there can be one or more
+ * iterations defined in the test case. Use END_ITERATION to end the iteration.
+ * Note that register and signature information will be reset for each
+ * iteration, however, the same set of configure chips will be used for all
+ * iterations within the test case.
+ */
+#define START_ITERATION                                                        \
+    {                                                                          \
+        simData.flushIterationData();
+
+/** This will add a SCOM register to the current iteration. */
+#define REG_SCOM(CHIP, ADDR, VAL)                                              \
+    simData.addScomReg(CHIP, static_cast<uint32_t>(ADDR),                      \
+                       static_cast<uint64_t>(VAL));
+
+/** This will add an Indirect SCOM register to the current iteration. */
+#define REG_IDSCOM(CHIP, ADDR, VAL)                                            \
+    simData.addIdScomReg(CHIP, static_cast<uint64_t>(ADDR),                    \
+                         static_cast<uint64_t>(VAL));
+
+/** This will add an expected signature to the current iteration. */
+#define EXP_SIG(CHIP, ID, INST, BIT, TYPE)                                     \
+    simData.addSignature(libhei::Signature{                                    \
+        CHIP, static_cast<libhei::RegisterId_t>(ID),                           \
+        static_cast<libhei::RegisterInstance_t>(INST),                         \
+        static_cast<libhei::RegisterBit_t>(BIT), libhei::ATTN_TYPE_##TYPE});
+
+/**
+ * This is the end of an iteration that began with START_ITERATION. All of the
+ * register contents and expected signatures will have been stored in the
+ * simulation data. So, this will call libhei::isolate() with the list of
+ * configured chips. Using the register contents in the simulation data,
+ * libhei::isolate() will return a list of signatures (active attentions). That
+ * list will be compared against the expected list of signatures stored in the
+ * simulation data for test case verification.
+ *
+ * You will see that there are two gtest checks for failures:
+ *  - The first check will look to see if any of the previous functions to add
+ *    chips, registers, or signatures to the simulation data failed.
+ *  - The second check will determine if isolation completed successfully and if
+ *    all expected signatures have been verified.
+ * If either check fails, the test case will be aborted regardless if there are
+ * additional iterations in that test case. Note that failure in a test case
+ * will not have any impact on subsequent test cases. Therefore, all test cases
+ * in a file will at least be attempted even if there is a failure.
+ */
+#define END_ITERATION                                                          \
+        if (HasFailure()) { simData.flushAll(); return; }                      \
+        simData.endIteration();                                                \
+        if (HasFailure()) { simData.flushAll(); return; }                      \
+    }
+
+/**
+ * This is the end of the test case that started with START_TEST_CASE. It will
+ * call libhei::uninitialize() and clean up the simulation data.
+ */
+#define END_TEST_CASE                                                          \
+        libhei::uninitialize();                                                \
+        simData.flushAll();                                                    \
+    }
+
+// clang-format on
diff --git a/test/simulator/user_interface.cpp b/test/simulator/user_interface.cpp
new file mode 100644
index 0000000..7ed998a
--- /dev/null
+++ b/test/simulator/user_interface.cpp
@@ -0,0 +1,79 @@
+/**
+ * @file These are the simulated implementations of the user interfaces declared
+ *       in hei_user_interface.hpp
+ */
+
+#include "simulator.hpp"
+
+#include <endian.h>
+
+#include <hei_user_interface.hpp>
+
+namespace libhei
+{
+
+//------------------------------------------------------------------------------
+
+ReturnCode registerRead(const Chip& i_chip, void* o_buffer, size_t& io_bufSize,
+                        uint64_t i_regType, uint64_t i_address)
+{
+    ReturnCode rc{};
+
+    HEI_ASSERT(nullptr != o_buffer);
+    HEI_ASSERT(0 != io_bufSize);
+
+    switch (i_regType)
+    {
+        // BEGIN temporary code
+        // TODO: add cases for REG_TYPE_SCOM and REG_TYPE_ID_SCOM
+        case REG_TYPE_SCOM:
+        {
+            uint64_t x = htobe64(0x8800000000000000);
+            memcpy(o_buffer, &x, sizeof(x));
+            break;
+        }
+        case REG_TYPE_ID_SCOM:
+        {
+            uint64_t x = htobe64(0x8000);
+            memcpy(o_buffer, &x, sizeof(x));
+            break;
+        }
+        // END temporary code
+        default:
+            rc = RC_REG_ACCESS_FAILURE;
+            HEI_ERR("registerRead(%p,%p,%lx,%lx,%lx)", i_chip.getChip(),
+                    o_buffer, io_bufSize, i_regType, i_address);
+    }
+
+    return rc;
+}
+
+//------------------------------------------------------------------------------
+
+#ifndef __HEI_READ_ONLY
+
+ReturnCode registerWrite(const Chip& i_chip, void* i_buffer, size_t& io_bufSize,
+                         uint64_t i_regType, uint64_t i_address)
+{
+    ReturnCode rc{};
+
+    HEI_ASSERT(nullptr != i_buffer);
+    HEI_ASSERT(0 != io_bufSize);
+
+    switch (i_regType)
+    {
+        // TODO: add cases for REG_TYPE_SCOM and REG_TYPE_ID_SCOM
+        default:
+            rc = RC_REG_ACCESS_FAILURE;
+            HEI_ERR("registerWrite(%p,%p,%lx,%lx,%lx)", i_chip.getChip(),
+                    i_buffer, io_bufSize, i_regType, i_address);
+    }
+
+    return rc;
+}
+
+#endif
+
+//------------------------------------------------------------------------------
+
+} // namespace libhei