diff --git a/test/openpower-pels/Makefile.include b/test/openpower-pels/Makefile.include
index 5705f73..18df9ec 100644
--- a/test/openpower-pels/Makefile.include
+++ b/test/openpower-pels/Makefile.include
@@ -10,6 +10,7 @@
 	pel_values_test \
 	pel_manager_test \
 	private_header_test \
+	registry_test \
 	repository_test \
 	section_header_test \
 	stream_test \
@@ -19,7 +20,9 @@
 	$(top_builddir)/extensions/openpower-pels/bcd_time.o \
 	$(top_builddir)/extensions/openpower-pels/log_id.o \
 	$(top_builddir)/extensions/openpower-pels/pel.o \
+	$(top_builddir)/extensions/openpower-pels/pel_values.o \
 	$(top_builddir)/extensions/openpower-pels/private_header.o \
+	$(top_builddir)/extensions/openpower-pels/registry.o \
 	$(top_builddir)/extensions/openpower-pels/user_header.o
 
 additional_data_test_SOURCES = %reldir%/additional_data_test.cpp
@@ -108,6 +111,16 @@
 	$(top_builddir)/extensions/openpower-pels/repository.o
 pel_manager_test_LDFLAGS = $(test_ldflags)
 
+registry_test_SOURCES = \
+	%reldir%/registry_test.cpp %reldir%/paths.cpp
+registry_test_CPPFLAGS = $(test_cppflags)
+registry_test_CXXFLAGS = $(test_cxxflags)
+registry_test_LDADD = \
+	$(test_ldadd) \
+	$(top_builddir)/extensions/openpower-pels/registry.o \
+	$(top_builddir)/extensions/openpower-pels/pel_values.o
+registry_test_LDFLAGS = $(test_ldflags)
+
 mtms_test_SOURCES = %reldir%/mtms_test.cpp
 mtms_test_CPPFLAGS = $(test_cppflags)
 mtms_test_CXXFLAGS = $(test_cxxflags)
diff --git a/test/openpower-pels/paths.cpp b/test/openpower-pels/paths.cpp
index 27f4bce..502fcf0 100644
--- a/test/openpower-pels/paths.cpp
+++ b/test/openpower-pels/paths.cpp
@@ -35,5 +35,18 @@
     return repoPath;
 }
 
+std::filesystem::path getMessageRegistryPath()
+{
+    static std::string registryPath;
+
+    if (registryPath.empty())
+    {
+        char templ[] = "/tmp/msgregtestXXXXXX";
+        registryPath = mkdtemp(templ);
+    }
+
+    return registryPath;
+}
+
 } // namespace pels
 } // namespace openpower
diff --git a/test/openpower-pels/pel_manager_test.cpp b/test/openpower-pels/pel_manager_test.cpp
index 0a82141..61fbedd 100644
--- a/test/openpower-pels/pel_manager_test.cpp
+++ b/test/openpower-pels/pel_manager_test.cpp
@@ -45,7 +45,8 @@
     std::vector<std::string> additionalData{adItem};
     std::vector<std::string> associations;
 
-    manager.create("error message", 42, 0, Entry::Level::Error, additionalData,
+    manager.create("error message", 42, 0,
+                   phosphor::logging::Entry::Level::Error, additionalData,
                    associations);
 
     // We don't know the exact name, but a file should have been added to the
diff --git a/test/openpower-pels/pel_utils.cpp b/test/openpower-pels/pel_utils.cpp
index 46ec8ed..3e0ac01 100644
--- a/test/openpower-pels/pel_utils.cpp
+++ b/test/openpower-pels/pel_utils.cpp
@@ -13,6 +13,7 @@
 std::filesystem::path CleanLogID::pelIDFile{};
 std::filesystem::path CleanPELFiles::pelIDFile{};
 std::filesystem::path CleanPELFiles::repoPath{};
+std::filesystem::path CleanPELFiles::registryPath{};
 
 constexpr uint8_t simplePEL[] = {
     // private header section header
diff --git a/test/openpower-pels/pel_utils.hpp b/test/openpower-pels/pel_utils.hpp
index 262a6e7..e61bea2 100644
--- a/test/openpower-pels/pel_utils.hpp
+++ b/test/openpower-pels/pel_utils.hpp
@@ -33,6 +33,7 @@
     {
         pelIDFile = openpower::pels::getPELIDFile();
         repoPath = openpower::pels::getPELRepoPath();
+        registryPath = openpower::pels::getMessageRegistryPath();
     }
 
     static void TearDownTestCase()
@@ -40,10 +41,12 @@
         std::filesystem::remove_all(
             std::filesystem::path{pelIDFile}.parent_path());
         std::filesystem::remove_all(repoPath);
+        std::filesystem::remove_all(registryPath);
     }
 
     static std::filesystem::path pelIDFile;
     static std::filesystem::path repoPath;
+    static std::filesystem::path registryPath;
 };
 
 /**
diff --git a/test/openpower-pels/registry_test.cpp b/test/openpower-pels/registry_test.cpp
new file mode 100644
index 0000000..2107725
--- /dev/null
+++ b/test/openpower-pels/registry_test.cpp
@@ -0,0 +1,166 @@
+#include "extensions/openpower-pels/registry.hpp"
+
+#include <filesystem>
+#include <fstream>
+#include <nlohmann/json.hpp>
+
+#include <gtest/gtest.h>
+
+using namespace openpower::pels::message;
+namespace fs = std::filesystem;
+
+const auto registryData = R"(
+{
+    "PELs":
+    [
+        {
+            "Name": "xyz.openbmc_project.Power.Fault",
+            "Subsystem": "power_supply",
+            "ActionFlags": ["service_action", "report"],
+
+            "SRC":
+            {
+                "ReasonCode": "0x2030"
+            }
+        },
+
+        {
+            "Name": "xyz.openbmc_project.Power.OverVoltage",
+            "Subsystem": "power_control_hw",
+            "Severity": "unrecoverable",
+            "MfgSeverity": "non_error",
+            "ActionFlags": ["service_action", "report", "call_home"],
+            "MfgActionFlags": ["hidden"],
+
+            "SRC":
+            {
+                "ReasonCode": "0x2333",
+                "Type": "BD",
+                "SymptomIDFields": ["SRCWord5", "SRCWord6", "SRCWord7"],
+                "PowerFault": true,
+                "Words6To9":
+                {
+                    "6":
+                    {
+                        "description": "Failing unit number",
+                        "AdditionalDataPropSource": "PS_NUM"
+                    },
+
+                    "7":
+                    {
+                        "description": "bad voltage",
+                        "AdditionalDataPropSource": "VOLTAGE"
+                    }
+                }
+            }
+        }
+    ]
+}
+)";
+
+class RegistryTest : public ::testing::Test
+{
+  protected:
+    static void SetUpTestCase()
+    {
+        char path[] = "/tmp/regtestXXXXXX";
+        regDir = mkdtemp(path);
+    }
+
+    static void TearDownTestCase()
+    {
+        fs::remove_all(regDir);
+    }
+
+    static std::string writeData(const char* data)
+    {
+        fs::path path = regDir / "registry.json";
+        std::ofstream stream{path};
+        stream << data;
+        return path;
+    }
+
+    static fs::path regDir;
+};
+
+fs::path RegistryTest::regDir{};
+
+TEST_F(RegistryTest, TestNoEntry)
+{
+    auto path = RegistryTest::writeData(registryData);
+    Registry registry{path};
+
+    auto entry = registry.lookup("foo");
+    EXPECT_FALSE(entry);
+}
+
+TEST_F(RegistryTest, TestFindEntry)
+{
+    auto path = RegistryTest::writeData(registryData);
+    Registry registry{path};
+
+    auto entry = registry.lookup("xyz.openbmc_project.Power.OverVoltage");
+    ASSERT_TRUE(entry);
+    EXPECT_EQ(entry->name, "xyz.openbmc_project.Power.OverVoltage");
+    EXPECT_EQ(entry->subsystem, 0x62);
+    EXPECT_EQ(*(entry->severity), 0x40);
+    EXPECT_EQ(*(entry->mfgSeverity), 0x00);
+    EXPECT_EQ(entry->actionFlags, 0xA800);
+    EXPECT_EQ(*(entry->mfgActionFlags), 0x4000);
+    EXPECT_FALSE(entry->eventType);
+    EXPECT_FALSE(entry->eventScope);
+
+    // TODO: compare SRC fields
+}
+
+// Check the entry that mostly uses defaults
+TEST_F(RegistryTest, TestFindEntryMinimal)
+{
+    auto path = RegistryTest::writeData(registryData);
+    Registry registry{path};
+
+    auto entry = registry.lookup("xyz.openbmc_project.Power.Fault");
+    ASSERT_TRUE(entry);
+    EXPECT_EQ(entry->name, "xyz.openbmc_project.Power.Fault");
+    EXPECT_EQ(entry->subsystem, 0x61);
+    EXPECT_FALSE(entry->severity);
+    EXPECT_FALSE(entry->mfgSeverity);
+    EXPECT_FALSE(entry->mfgActionFlags);
+    EXPECT_EQ(entry->actionFlags, 0xA000);
+    EXPECT_FALSE(entry->eventType);
+    EXPECT_FALSE(entry->eventScope);
+}
+
+TEST_F(RegistryTest, TestBadJSON)
+{
+    auto path = RegistryTest::writeData("bad {} json");
+
+    Registry registry{path};
+
+    EXPECT_FALSE(registry.lookup("foo"));
+}
+
+// Test the helper functions the use the pel_values data.
+TEST_F(RegistryTest, TestHelperFunctions)
+{
+    using namespace openpower::pels::message::helper;
+    EXPECT_EQ(getSubsystem("input_power_source"), 0xA1);
+    EXPECT_THROW(getSubsystem("foo"), std::runtime_error);
+
+    EXPECT_EQ(getSeverity("symptom_recovered"), 0x71);
+    EXPECT_THROW(getSeverity("foo"), std::runtime_error);
+
+    EXPECT_EQ(getEventType("dump_notification"), 0x08);
+    EXPECT_THROW(getEventType("foo"), std::runtime_error);
+
+    EXPECT_EQ(getEventScope("possibly_multiple_platforms"), 0x04);
+    EXPECT_THROW(getEventScope("foo"), std::runtime_error);
+
+    std::vector<std::string> flags{"service_action", "dont_report",
+                                   "termination"};
+    EXPECT_EQ(getActionFlags(flags), 0x9100);
+
+    flags.clear();
+    flags.push_back("foo");
+    EXPECT_THROW(getActionFlags(flags), std::runtime_error);
+}