diff --git a/test/openpower-pels/Makefile.include b/test/openpower-pels/Makefile.include
index e54bce8..ccd5d26 100644
--- a/test/openpower-pels/Makefile.include
+++ b/test/openpower-pels/Makefile.include
@@ -20,6 +20,7 @@
 	repository_test \
 	section_header_test \
 	severity_test \
+	src_callout_test \
 	stream_test \
 	user_data_test \
 	user_header_test
@@ -227,3 +228,17 @@
 	$(test_ldadd) \
 	$(top_builddir)/extensions/openpower-pels/mru.o
 mru_test_LDFLAGS = $(test_ldflags)
+
+src_callout_test_SOURCES = \
+	%reldir%/src_callout_test.cpp \
+	%reldir%/pel_utils.cpp
+src_callout_test_CPPFLAGS = $(test_cppflags)
+src_callout_test_CXXFLAGS = $(test_cxxflags)
+src_callout_test_LDADD = \
+	$(test_ldadd) \
+	$(top_builddir)/extensions/openpower-pels/callout.o \
+	$(top_builddir)/extensions/openpower-pels/fru_identity.o \
+	$(top_builddir)/extensions/openpower-pels/mru.o \
+	$(top_builddir)/extensions/openpower-pels/mtms.o \
+	$(top_builddir)/extensions/openpower-pels/pce_identity.o
+src_callout_test_LDFLAGS = $(test_ldflags)
diff --git a/test/openpower-pels/pel_utils.cpp b/test/openpower-pels/pel_utils.cpp
index 3e0ac01..3610dd7 100644
--- a/test/openpower-pels/pel_utils.cpp
+++ b/test/openpower-pels/pel_utils.cpp
@@ -51,6 +51,33 @@
     // Add more as the code supports more
 };
 
+std::vector<uint8_t> srcFRUIdentityCallout{
+    'I', 'D', 0x1C, 0x1D,                     // type, size, flags
+    '1', '2', '3',  '4',                      // PN
+    '5', '6', '7',  0x00, 'A', 'A', 'A', 'A', // CCIN
+    '1', '2', '3',  '4',  '5', '6', '7', '8', // SN
+    '9', 'A', 'B',  'C'};
+
+std::vector<uint8_t> srcPCEIdentityCallout{
+    'P', 'E', 0x24, 0x00,                      // type, size, flags
+    'T', 'T', 'T',  'T',  '-', 'M', 'M',  'M', // MTM
+    '1', '2', '3',  '4',  '5', '6', '7',       // SN
+    '8', '9', 'A',  'B',  'C', 'P', 'C',  'E', // Name + null padded
+    'N', 'A', 'M',  'E',  '1', '2', 0x00, 0x00, 0x00};
+
+std::vector<uint8_t> srcMRUCallout{
+    'M',  'R',  0x28, 0x04, // ID, size, flags
+    0x00, 0x00, 0x00, 0x00, // Reserved
+    0x00, 0x00, 0x00, 'H',  // priority 0
+    0x01, 0x01, 0x01, 0x01, // MRU ID 0
+    0x00, 0x00, 0x00, 'M',  // priority 1
+    0x02, 0x02, 0x02, 0x02, // MRU ID 1
+    0x00, 0x00, 0x00, 'L',  // priority 2
+    0x03, 0x03, 0x03, 0x03, // MRU ID 2
+    0x00, 0x00, 0x00, 'H',  // priority 3
+    0x04, 0x04, 0x04, 0x04, // MRU ID 3
+};
+
 std::unique_ptr<std::vector<uint8_t>> pelDataFactory(TestPelType type)
 {
     std::unique_ptr<std::vector<uint8_t>> data;
@@ -74,6 +101,22 @@
     return data;
 }
 
+std::vector<uint8_t> srcDataFactory(TestSRCType type)
+{
+    switch (type)
+    {
+        case TestSRCType::fruIdentityStructure:
+            return srcFRUIdentityCallout;
+
+        case TestSRCType::pceIdentityStructure:
+            return srcPCEIdentityCallout;
+
+        case TestSRCType::mruStructure:
+            return srcMRUCallout;
+    }
+    return {};
+}
+
 std::unique_ptr<std::vector<uint8_t>> readPELFile(const fs::path& path)
 {
     std::ifstream file{path};
diff --git a/test/openpower-pels/pel_utils.hpp b/test/openpower-pels/pel_utils.hpp
index e61bea2..2d40033 100644
--- a/test/openpower-pels/pel_utils.hpp
+++ b/test/openpower-pels/pel_utils.hpp
@@ -60,6 +60,16 @@
 };
 
 /**
+ * @brief Tells the SRC factory which data to create
+ */
+enum class TestSRCType
+{
+    fruIdentityStructure,
+    pceIdentityStructure,
+    mruStructure,
+};
+
+/**
  * @brief PEL data factory, for testing
  *
  * @param[in] type - the type of data to create
@@ -69,6 +79,17 @@
 std::unique_ptr<std::vector<uint8_t>> pelDataFactory(TestPelType type);
 
 /**
+ * @brief SRC data factory, for testing
+ *
+ * Provides pieces of the SRC PEL section, such as a callout.
+ *
+ * @param[in] type - the type of data to create
+ *
+ * @return std::vector<uint8_t> - The SRC data
+ */
+std::vector<uint8_t> srcDataFactory(TestSRCType type);
+
+/**
  * @brief Helper function to read raw PEL data from a file
  *
  * @param[in] path - the path to read
diff --git a/test/openpower-pels/src_callout_test.cpp b/test/openpower-pels/src_callout_test.cpp
new file mode 100644
index 0000000..0a78c94
--- /dev/null
+++ b/test/openpower-pels/src_callout_test.cpp
@@ -0,0 +1,146 @@
+#include "extensions/openpower-pels/callout.hpp"
+#include "pel_utils.hpp"
+
+#include <gtest/gtest.h>
+
+using namespace openpower::pels;
+using namespace openpower::pels::src;
+
+// Unflatten the callout section with all three substructures
+TEST(CalloutTest, TestUnflattenAllSubstructures)
+{
+    // The base data.
+    std::vector<uint8_t> data{
+        0xFF, 0x2F, 'H', 8, // size, flags, priority, LC length
+        'U',  '1',  '2', '-', 'P', '1', 0x00, 0x00 // LC
+    };
+
+    auto fruIdentity = srcDataFactory(TestSRCType::fruIdentityStructure);
+    auto pceIdentity = srcDataFactory(TestSRCType::pceIdentityStructure);
+    auto mrus = srcDataFactory(TestSRCType::mruStructure);
+
+    // Add all 3 substructures
+    data.insert(data.end(), fruIdentity.begin(), fruIdentity.end());
+    data.insert(data.end(), pceIdentity.begin(), pceIdentity.end());
+    data.insert(data.end(), mrus.begin(), mrus.end());
+
+    // The final size
+    data[0] = data.size();
+
+    Stream stream{data};
+    Callout callout{stream};
+
+    EXPECT_EQ(callout.flattenedSize(), data.size());
+    EXPECT_EQ(callout.priority(), 'H');
+    EXPECT_EQ(callout.locationCode(), "U12-P1");
+
+    // Spot check the 3 substructures
+    EXPECT_TRUE(callout.fruIdentity());
+    EXPECT_EQ(callout.fruIdentity()->getSN(), "123456789ABC");
+
+    EXPECT_TRUE(callout.pceIdentity());
+    EXPECT_EQ(callout.pceIdentity()->enclosureName(), "PCENAME12");
+
+    EXPECT_TRUE(callout.mru());
+    EXPECT_EQ(callout.mru()->mrus().size(), 4);
+    EXPECT_EQ(callout.mru()->mrus().at(3).id, 0x04040404);
+
+    // Now flatten
+    std::vector<uint8_t> newData;
+    Stream newStream{newData};
+
+    callout.flatten(newStream);
+    EXPECT_EQ(data, newData);
+}
+
+TEST(CalloutTest, TestUnflattenOneSubstructure)
+{
+    std::vector<uint8_t> data{
+        0xFF, 0x28, 'H', 0x08, // size, flags, priority, LC length
+        'U',  '1',  '2', '-',  'P', '1', 0x00, 0x00 // LC
+    };
+
+    auto fruIdentity = srcDataFactory(TestSRCType::fruIdentityStructure);
+
+    data.insert(data.end(), fruIdentity.begin(), fruIdentity.end());
+
+    // The final size
+    data[0] = data.size();
+
+    Stream stream{data};
+    Callout callout{stream};
+
+    EXPECT_EQ(callout.flattenedSize(), data.size());
+
+    // Spot check the substructure
+    EXPECT_TRUE(callout.fruIdentity());
+    EXPECT_EQ(callout.fruIdentity()->getSN(), "123456789ABC");
+
+    // Not present
+    EXPECT_FALSE(callout.pceIdentity());
+    EXPECT_FALSE(callout.mru());
+
+    // Now flatten
+    std::vector<uint8_t> newData;
+    Stream newStream{newData};
+
+    callout.flatten(newStream);
+    EXPECT_EQ(data, newData);
+}
+
+TEST(CalloutTest, TestUnflattenTwoSubstructures)
+{
+    std::vector<uint8_t> data{
+        0xFF, 0x2B, 'H', 0x08, // size, flags, priority, LC length
+        'U',  '1',  '2', '-',  'P', '1', 0x00, 0x00 // LC
+    };
+
+    auto fruIdentity = srcDataFactory(TestSRCType::fruIdentityStructure);
+    auto pceIdentity = srcDataFactory(TestSRCType::pceIdentityStructure);
+
+    data.insert(data.end(), fruIdentity.begin(), fruIdentity.end());
+    data.insert(data.end(), pceIdentity.begin(), pceIdentity.end());
+
+    // The final size
+    data[0] = data.size();
+
+    Stream stream{data};
+    Callout callout{stream};
+
+    EXPECT_EQ(callout.flattenedSize(), data.size());
+
+    // Spot check the 2 substructures
+    EXPECT_TRUE(callout.fruIdentity());
+    EXPECT_EQ(callout.fruIdentity()->getSN(), "123456789ABC");
+
+    EXPECT_TRUE(callout.pceIdentity());
+    EXPECT_EQ(callout.pceIdentity()->enclosureName(), "PCENAME12");
+
+    // Not present
+    EXPECT_FALSE(callout.mru());
+
+    // Now flatten
+    std::vector<uint8_t> newData;
+    Stream newStream{newData};
+
+    callout.flatten(newStream);
+    EXPECT_EQ(data, newData);
+}
+
+TEST(CalloutTest, TestNoLocationCode)
+{
+    std::vector<uint8_t> data{
+        0xFF, 0x2B, 'H', 0x00 // size, flags, priority, LC length
+    };
+
+    auto fruIdentity = srcDataFactory(TestSRCType::fruIdentityStructure);
+    data.insert(data.end(), fruIdentity.begin(), fruIdentity.end());
+
+    // The final size
+    data[0] = data.size();
+
+    Stream stream{data};
+    Callout callout{stream};
+
+    EXPECT_TRUE(callout.locationCode().empty());
+}