diff --git a/src/tests/backend/plugin/test_plugin.h b/src/tests/backend/plugin/test_plugin.h
index 061b4862..61c90200 100644
--- a/src/tests/backend/plugin/test_plugin.h
+++ b/src/tests/backend/plugin/test_plugin.h
@@ -31,39 +31,243 @@ along with LOOT.  If not, see
 class Plugin : public SkyrimTest {};
 
 TEST_F(Plugin, ConstructorsAndDataAccess) {
-    FAIL() << "Test is unimplemented";
+    loot::Plugin plugin;
+    EXPECT_EQ("", plugin.Name());
+    EXPECT_TRUE(plugin.FormIDs().empty());
+    EXPECT_TRUE(plugin.Masters().empty());
+    EXPECT_FALSE(plugin.IsMaster());
+    EXPECT_TRUE(plugin.IsEmpty());
+    EXPECT_EQ("", plugin.Version());
+    EXPECT_EQ(0, plugin.Crc());
+
+    plugin = loot::Plugin("Blank.esm");
+    EXPECT_EQ("Blank.esm", plugin.Name());
+    EXPECT_TRUE(plugin.FormIDs().empty());
+    EXPECT_TRUE(plugin.Masters().empty());
+    EXPECT_FALSE(plugin.IsMaster());
+    EXPECT_TRUE(plugin.IsEmpty());
+    EXPECT_EQ("", plugin.Version());
+    EXPECT_EQ(0, plugin.Crc());
+
+    loot::Game game(loot::Game::tes5);
+    game.SetGamePath(dataPath.parent_path());
+    ASSERT_NO_THROW(game.Init(false, localPath));
+
+    plugin = loot::Plugin(game, "Blank.esm", true);
+    EXPECT_EQ("Blank.esm", plugin.Name());
+    EXPECT_TRUE(plugin.FormIDs().empty());
+    EXPECT_TRUE(plugin.Masters().empty());
+    EXPECT_TRUE(plugin.IsMaster());
+    EXPECT_FALSE(plugin.IsEmpty());
+    EXPECT_EQ("5.0", plugin.Version());
+    EXPECT_EQ(0, plugin.Crc());
+
+    plugin = loot::Plugin(game, "Blank.esm", false);
+    EXPECT_EQ("Blank.esm", plugin.Name());
+    EXPECT_EQ(std::set<loot::FormID>({
+        loot::FormID("Blank.esm", 0xCF0),
+        loot::FormID("Blank.esm", 0xCF1),
+        loot::FormID("Blank.esm", 0xCF2),
+        loot::FormID("Blank.esm", 0xCF3),
+        loot::FormID("Blank.esm", 0xCF4),
+        loot::FormID("Blank.esm", 0xCF5),
+        loot::FormID("Blank.esm", 0xCF6),
+        loot::FormID("Blank.esm", 0xCF7),
+        loot::FormID("Blank.esm", 0xCF8),
+        loot::FormID("Blank.esm", 0xCF9),
+    }), plugin.FormIDs());
+    EXPECT_TRUE(plugin.Masters().empty());
+    EXPECT_TRUE(plugin.IsMaster());
+    EXPECT_FALSE(plugin.IsEmpty());
+    EXPECT_EQ("5.0", plugin.Version());
+    EXPECT_EQ(0xD33753E4, plugin.Crc());
+
+    plugin = loot::Plugin(game, "Blank - Master Dependent.esp", false);
+    EXPECT_EQ("Blank - Master Dependent.esp", plugin.Name());
+    EXPECT_FALSE(plugin.IsEmpty());
+    EXPECT_FALSE(plugin.IsMaster());
+    EXPECT_EQ(std::set<loot::FormID>({
+        loot::FormID("Blank.esm", 0xCF0),
+        loot::FormID("Blank.esm", 0xCF1),
+        loot::FormID("Blank - Master Dependent.esp", 0xCE9),
+        loot::FormID("Blank - Master Dependent.esp", 0xCEA),
+    }), plugin.FormIDs());
+    EXPECT_EQ(std::vector<std::string>({
+        "Blank.esm"
+    }), plugin.Masters());
+    EXPECT_EQ("", plugin.Version());
+    EXPECT_EQ(0x832152DC, plugin.Crc());
 }
 
 TEST_F(Plugin, LoadsBSA) {
-    FAIL() << "Test is unimplemented";
+    loot::Game game(loot::Game::tes5);
+    game.SetGamePath(dataPath.parent_path());
+    ASSERT_NO_THROW(game.Init(false, localPath));
+
+    loot::Plugin plugin("Blank - Different.esm");
+    EXPECT_FALSE(plugin.LoadsBSA(game));
+
+    plugin = loot::Plugin("Blank\\.esm");
+    EXPECT_FALSE(plugin.LoadsBSA(game));
+
+    plugin = loot::Plugin("Blank.esm");
+    EXPECT_TRUE(plugin.LoadsBSA(game));
 }
 
 TEST_F(Plugin, IsValid) {
-    FAIL() << "Test is unimplemented";
+    loot::Game game(loot::Game::tes5);
+    game.SetGamePath(dataPath.parent_path());
+    ASSERT_NO_THROW(game.Init(false, localPath));
+
+    loot::Plugin plugin("Blank.esm");
+    EXPECT_TRUE(plugin.IsValid(game));
+
+    plugin = loot::Plugin("NotAPlugin.esm");
+    EXPECT_FALSE(plugin.IsValid(game));
+
+    plugin = loot::Plugin("EmptyFile.esm");
+    EXPECT_FALSE(plugin.IsValid(game));
 }
 
 TEST_F(Plugin, IsActive) {
-    FAIL() << "Test is unimplemented";
+    loot::Game game(loot::Game::tes5);
+    game.SetGamePath(dataPath.parent_path());
+    ASSERT_NO_THROW(game.Init(false, localPath));
+
+    loot::Plugin plugin("Blank.esm");
+    EXPECT_TRUE(plugin.IsActive(game));
+
+    plugin = loot::Plugin("Blank.esp");
+    EXPECT_FALSE(plugin.IsActive(game));
 }
 
 TEST_F(Plugin, EqualityOperator) {
-    FAIL() << "Test is unimplemented";
+    loot::Plugin plugin1, plugin2;
+    EXPECT_TRUE(plugin1 == plugin2);
+
+    plugin1 = loot::Plugin("Blank.esm");
+    plugin2 = loot::Plugin("blank.esm");
+    EXPECT_TRUE(plugin1 == plugin2);
+
+    plugin1 = loot::Plugin("Blank.esm");
+    plugin2 = loot::Plugin("Blank.esp");
+    EXPECT_FALSE(plugin1 == plugin2);
 }
 
 TEST_F(Plugin, InequalityOperator) {
-    FAIL() << "Test is unimplemented";
+    loot::Plugin plugin1, plugin2;
+    EXPECT_FALSE(plugin1 != plugin2);
+
+    plugin1 = loot::Plugin("Blank.esm");
+    plugin2 = loot::Plugin("blank.esm");
+    EXPECT_FALSE(plugin1 != plugin2);
+
+    plugin1 = loot::Plugin("Blank.esm");
+    plugin2 = loot::Plugin("Blank.esp");
+    EXPECT_TRUE(plugin1 != plugin2);
 }
 
 TEST_F(Plugin, DoFormIDsOverlap) {
-    FAIL() << "Test is unimplemented";
+    loot::Game game(loot::Game::tes5);
+    game.SetGamePath(dataPath.parent_path());
+    ASSERT_NO_THROW(game.Init(false, localPath));
+
+    loot::Plugin plugin1, plugin2;
+    EXPECT_FALSE(plugin1.DoFormIDsOverlap(plugin2));
+    EXPECT_FALSE(plugin2.DoFormIDsOverlap(plugin1));
+
+    plugin1 = loot::Plugin(game, "Blank.esm", true);
+    plugin2 = loot::Plugin(game, "Blank - Master Dependent.esm", true);
+    EXPECT_FALSE(plugin1.DoFormIDsOverlap(plugin2));
+    EXPECT_FALSE(plugin2.DoFormIDsOverlap(plugin1));
+
+    plugin1 = loot::Plugin(game, "Blank.esm", false);
+    plugin2 = loot::Plugin(game, "Blank.esp", false);
+    EXPECT_FALSE(plugin1.DoFormIDsOverlap(plugin2));
+    EXPECT_FALSE(plugin2.DoFormIDsOverlap(plugin1));
+
+    plugin1 = loot::Plugin(game, "Blank.esm", false);
+    plugin2 = loot::Plugin(game, "Blank - Master Dependent.esm", false);
+    EXPECT_TRUE(plugin1.DoFormIDsOverlap(plugin2));
+    EXPECT_TRUE(plugin2.DoFormIDsOverlap(plugin1));
 }
 
 TEST_F(Plugin, OverlapFormIDs) {
-    FAIL() << "Test is unimplemented";
+    loot::Game game(loot::Game::tes5);
+    game.SetGamePath(dataPath.parent_path());
+    ASSERT_NO_THROW(game.Init(false, localPath));
+
+    loot::Plugin plugin1, plugin2;
+    EXPECT_TRUE(plugin1.OverlapFormIDs(plugin2).empty());
+    EXPECT_TRUE(plugin2.OverlapFormIDs(plugin1).empty());
+
+    plugin1 = loot::Plugin(game, "Blank.esm", true);
+    plugin2 = loot::Plugin(game, "Blank - Master Dependent.esm", true);
+    EXPECT_TRUE(plugin1.OverlapFormIDs(plugin2).empty());
+    EXPECT_TRUE(plugin2.OverlapFormIDs(plugin1).empty());
+
+    plugin1 = loot::Plugin(game, "Blank.esm", false);
+    plugin2 = loot::Plugin(game, "Blank.esp", false);
+    EXPECT_TRUE(plugin1.OverlapFormIDs(plugin2).empty());
+    EXPECT_TRUE(plugin2.OverlapFormIDs(plugin1).empty());
+
+    plugin1 = loot::Plugin(game, "Blank.esm", false);
+    plugin2 = loot::Plugin(game, "Blank - Master Dependent.esm", false);
+    EXPECT_EQ(std::set<loot::FormID>({
+        loot::FormID("Blank.esm", 0xCF0),
+        loot::FormID("Blank.esm", 0xCF1),
+        loot::FormID("Blank.esm", 0xCF2),
+        loot::FormID("Blank.esm", 0xCF3),
+    }), plugin1.OverlapFormIDs(plugin2));
+    EXPECT_EQ(std::set<loot::FormID>({
+        loot::FormID("Blank.esm", 0xCF0),
+        loot::FormID("Blank.esm", 0xCF1),
+        loot::FormID("Blank.esm", 0xCF2),
+        loot::FormID("Blank.esm", 0xCF3),
+    }), plugin2.OverlapFormIDs(plugin1));
 }
 
 TEST_F(Plugin, CheckInstallValidity) {
-    FAIL() << "Test is unimplemented";
+    loot::Game game(loot::Game::tes5);
+    game.SetGamePath(dataPath.parent_path());
+    ASSERT_NO_THROW(game.Init(false, localPath));
+
+    loot::Plugin plugin;
+    EXPECT_FALSE(plugin.CheckInstallValidity(game));
+    EXPECT_TRUE(plugin.Messages().empty());
+
+    plugin = loot::Plugin(game, "Blank.esm", false);
+    plugin.Reqs({
+        loot::File("Blank.missing.esm"),
+        loot::File("Blank.esp"),
+        loot::File("Blank - Master Dependent.esm"),
+    });
+    plugin.Incs({
+        loot::File("Blank - Different.esm"),
+        loot::File("Skyrim.esm"),
+    });
+    plugin.DirtyInfo({
+        loot::PluginDirtyInfo(0xD33753E4, 0, 1, 2, "utility1"),
+        loot::PluginDirtyInfo(0xDEADBEEF, 0, 5, 10, "utility2"),
+    });
+    EXPECT_TRUE(plugin.CheckInstallValidity(game));
+    EXPECT_EQ(std::list<loot::Message>({
+        loot::Message(loot::Message::error, "This plugin requires \"Blank.missing.esm\" to be installed, but it is missing."),
+        loot::Message(loot::Message::error, "This plugin is incompatible with \"Skyrim.esm\", but both are present."),
+        loot::PluginDirtyInfo(0xD33753E4, 0, 1, 2, "utility1").AsMessage(),
+        loot::PluginDirtyInfo(0xDEADBEEF, 0, 5, 10, "utility2").AsMessage(),
+    }), plugin.Messages());
+
+    plugin = loot::Plugin(game, "Blank - Different Master Dependent.esp", false);
+    EXPECT_FALSE(plugin.CheckInstallValidity(game));
+    EXPECT_EQ(std::list<loot::Message>({
+        loot::Message(loot::Message::error, "This plugin requires \"Blank - Different.esm\" to be active, but it is inactive."),
+    }), plugin.Messages());
+
+    plugin = loot::Plugin("Blank - Different Master Dependent.esp");
+    plugin.Tags({loot::Tag("Filter")});
+    EXPECT_FALSE(plugin.CheckInstallValidity(game));
+    EXPECT_TRUE(plugin.Messages().empty());
 }
 
 #endif
diff --git a/src/tests/fixtures.h b/src/tests/fixtures.h
index 9236be94..89770fb4 100644
--- a/src/tests/fixtures.h
+++ b/src/tests/fixtures.h
@@ -269,7 +269,8 @@ protected:
         // Set Skyrim's active plugins to a known list before running the test.
         loot::ofstream activePlugins(localPath / "plugins.txt");
         activePlugins
-            << "Blank.esm" << std::endl;
+            << "Blank.esm" << std::endl
+            << "Blank - Different Master Dependent.esp" << std::endl;
         activePlugins.close();
     }