Load the associations definitions

Parse the JSON file to load in the _associations
data structures.  Any failures will cause an exception
to be thrown that will crash the app.

The JSON looks like:

[
    {
        "path": "The relative path of the inventory object to create the
                 org.openbmc.Associations interface on."
        "endpoints":
        [
            {
                "types":
                {
                    "fType": "The forward association type."
                    "rType": "The reverse association type."
                },
                "paths":
                [
                    "The list of association endpoints for this
                     inventory path and association type."
                ]
            }
        ]
    }
]

Change-Id: I098fdc607f0c3ab2861f9b33e3e0d46e4989bd7a
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/test/associations_test.cpp b/test/associations_test.cpp
new file mode 100644
index 0000000..357659d
--- /dev/null
+++ b/test/associations_test.cpp
@@ -0,0 +1,302 @@
+#include "association_manager.hpp"
+
+#include <filesystem>
+#include <fstream>
+
+#include <gtest/gtest.h>
+
+using namespace phosphor::inventory::manager::associations;
+namespace fs = std::filesystem;
+
+static const auto goodJson = R"(
+[
+    {
+        "path": "system/PS0",
+        "endpoints":
+        [
+            {
+                "types":
+                {
+                    "rType": "inventory",
+                    "fType": "sensors"
+                },
+                "paths":
+                [
+                    "power/ps0_input_power",
+                    "voltage/ps0_input_voltage",
+                    "current/ps0_output_current",
+                    "voltage/ps0_output_voltage"
+                ]
+            },
+            {
+                "types":
+                {
+                    "rType": "inventory",
+                    "fType": "fans"
+                },
+                "paths":
+                [
+                    "fan_tach/ps0_fan"
+                ]
+            }
+        ]
+    },
+    {
+        "path": "system/fan42",
+        "endpoints":
+        [
+            {
+                "types":
+                {
+                    "rType": "inventory",
+                    "fType": "sensors"
+                },
+                "paths":
+                [
+                    "fan_tach/fan42"
+                ]
+            },
+            {
+                "types":
+                {
+                    "rType": "inventory",
+                    "fType": "led"
+                },
+                "paths":
+                [
+                    "led/fan42"
+                ]
+            }
+        ]
+    }
+])";
+
+// Malformed JSON
+static const auto badJson0 = R"(
+    "hello": world
+})";
+
+// Uses 'blah' instead of 'paths'
+static const auto badJson1 = R"(
+[
+    {
+        "blah": "system/PS0",
+        "endpoints":
+        [
+            {
+                "types":
+                {
+                    "fType": "inventory",
+                    "rType": "sensors"
+                },
+                "paths":
+                [
+                    "ps0_input_power",
+                ]
+            }
+        ]
+    }
+])";
+
+// Uses 'blah' instead of 'rType'
+static const auto badJson2 = R"(
+[
+    {
+        "paths": "system/PS0",
+        "endpoints":
+        [
+            {
+                "types":
+                {
+                    "blah": "inventory",
+                    "fType": "sensors"
+                },
+                "paths":
+                [
+                    "ps0_input_power",
+                ]
+            }
+        ]
+    }
+])";
+
+// Missing the endpoints/paths array
+static const auto badJson3 = R"(
+[
+    {
+        "paths": "system/PS0",
+        "endpoints":
+        [
+            {
+                "types":
+                {
+                    "rType": "inventory",
+                    "fType": "sensors"
+                }
+            }
+        ]
+    }
+])";
+
+class AssocsTest : public ::testing::Test
+{
+  protected:
+    AssocsTest() : ::testing::Test(), bus(sdbusplus::bus::new_default())
+    {
+    }
+
+    fs::path jsonDir;
+    sdbusplus::bus::bus bus;
+
+    virtual void SetUp()
+    {
+        char dir[] = {"assocTestXXXXXX"};
+        jsonDir = mkdtemp(dir);
+    }
+
+    virtual void TearDown()
+    {
+        fs::remove_all(jsonDir);
+    }
+
+    std::string writeFile(const char* data)
+    {
+        fs::path path = jsonDir / "associations.json";
+
+        std::ofstream f{path};
+        f << data;
+        f.close();
+
+        return path;
+    }
+};
+
+TEST_F(AssocsTest, TEST_NO_JSON)
+{
+    try
+    {
+        Manager m{bus};
+        EXPECT_TRUE(false);
+    }
+    catch (std::exception& e)
+    {
+    }
+}
+
+TEST_F(AssocsTest, TEST_GOOD_JSON)
+{
+    auto path = writeFile(goodJson);
+    Manager m(bus, path);
+
+    const auto& a = m.getAssociationsConfig();
+    EXPECT_EQ(a.size(), 2);
+
+    {
+        auto x = a.find("/xyz/openbmc_project/inventory/system/PS0");
+        EXPECT_NE(x, a.end());
+
+        auto& endpoints = x->second;
+        EXPECT_EQ(endpoints.size(), 2);
+
+        {
+            auto& types = std::get<0>(endpoints[0]);
+            EXPECT_EQ(std::get<0>(types), "sensors");
+            EXPECT_EQ(std::get<1>(types), "inventory");
+
+            auto& paths = std::get<1>(endpoints[0]);
+            EXPECT_EQ(paths.size(), 4);
+        }
+        {
+            auto& types = std::get<0>(endpoints[1]);
+            EXPECT_EQ(std::get<0>(types), "fans");
+            EXPECT_EQ(std::get<1>(types), "inventory");
+
+            auto& paths = std::get<1>(endpoints[1]);
+            EXPECT_EQ(paths.size(), 1);
+        }
+    }
+    {
+        auto x = a.find("/xyz/openbmc_project/inventory/system/fan42");
+        EXPECT_NE(x, a.end());
+
+        auto& endpoints = x->second;
+        EXPECT_EQ(endpoints.size(), 2);
+
+        {
+            auto& types = std::get<0>(endpoints[0]);
+            EXPECT_EQ(std::get<0>(types), "sensors");
+            EXPECT_EQ(std::get<1>(types), "inventory");
+
+            auto& paths = std::get<1>(endpoints[0]);
+            EXPECT_EQ(paths.size(), 1);
+        }
+        {
+            auto& types = std::get<0>(endpoints[1]);
+            EXPECT_EQ(std::get<0>(types), "led");
+            EXPECT_EQ(std::get<1>(types), "inventory");
+
+            auto& paths = std::get<1>(endpoints[1]);
+            EXPECT_EQ(paths.size(), 1);
+        }
+    }
+}
+
+TEST_F(AssocsTest, TEST_BAD_JSON0)
+{
+    auto path = writeFile(badJson0);
+
+    try
+    {
+        Manager m(bus, path);
+
+        EXPECT_TRUE(false);
+    }
+    catch (std::exception& e)
+    {
+    }
+}
+
+TEST_F(AssocsTest, TEST_BAD_JSON1)
+{
+    auto path = writeFile(badJson1);
+
+    try
+    {
+        Manager m(bus, path);
+
+        EXPECT_TRUE(false);
+    }
+    catch (std::exception& e)
+    {
+    }
+}
+
+TEST_F(AssocsTest, TEST_BAD_JSON2)
+{
+    auto path = writeFile(badJson2);
+
+    try
+    {
+        Manager m(bus, path);
+
+        EXPECT_TRUE(false);
+    }
+    catch (std::exception& e)
+    {
+    }
+}
+
+TEST_F(AssocsTest, TEST_BAD_JSON3)
+{
+    auto path = writeFile(badJson3);
+
+    try
+    {
+        Manager m(bus, path);
+
+        EXPECT_TRUE(false);
+    }
+    catch (std::exception& e)
+    {
+    }
+}