meson: separate meson.build for tests

Separate build file reduces indentation and makes things more readable.

Tested: Unit Tests Pass

```
Running all tests
1/4 test_systemd_parser                   OK              0.03s
2/4 test_systemd_signal                   OK              0.02s
3/4 test_scheduled_host_transition        OK              0.01s
4/4 test_hypervisor_state                 OK              0.01s

Ok:                4
Fail:              0
```

Change-Id: I369d00698eddad28834aeebc5455fe9387019f9d
Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com>
diff --git a/test/meson.build b/test/meson.build
new file mode 100644
index 0000000..ef56b48
--- /dev/null
+++ b/test/meson.build
@@ -0,0 +1,65 @@
+
+test(
+    'test_systemd_parser',
+    executable(
+        'test_systemd_parser',
+        'systemd_parser.cpp',
+        '../systemd_target_parser.cpp',
+        dependencies: [gtest, nlohmann_json_dep],
+        implicit_include_directories: true,
+        include_directories: '../',
+    ),
+)
+
+test(
+    'test_systemd_signal',
+    executable(
+        'test_systemd_signal',
+        'systemd_signal.cpp',
+        '../systemd_target_signal.cpp',
+        '../utils.cpp',
+        dependencies: [
+            gtest,
+            libgpiod,
+            nlohmann_json_dep,
+            phosphorlogging,
+            sdbusplus,
+            sdeventplus,
+        ],
+        implicit_include_directories: true,
+        include_directories: '../',
+    ),
+)
+
+test(
+    'test_scheduled_host_transition',
+    executable(
+        'test_scheduled_host_transition',
+        'test_scheduled_host_transition.cpp',
+        '../scheduled_host_transition.cpp',
+        '../utils.cpp',
+        dependencies: [
+            cereal,
+            gmock,
+            gtest,
+            libgpiod,
+            phosphorlogging,
+            sdbusplus,
+            sdeventplus,
+        ],
+        implicit_include_directories: true,
+        include_directories: '../',
+    ),
+)
+
+test(
+    'test_hypervisor_state',
+    executable(
+        'test_hypervisor_state',
+        'hypervisor_state.cpp',
+        '../hypervisor_state_manager.cpp',
+        dependencies: [gtest, phosphorlogging, sdbusplus, sdeventplus],
+        implicit_include_directories: true,
+        include_directories: '../',
+    ),
+)