Added unit and integration tests

tests/bin/gman/main_tests.rs

@@ -0,0 +1,22 @@
+use gman::providers::SupportedProvider;
+use gman::providers::local::LocalProvider;
+use pretty_assertions::assert_eq;
+
+#[test]
+fn test_provider_kind_from() {
+    enum ProviderKind {
+        Local,
+    }
+
+    impl From<ProviderKind> for SupportedProvider {
+        fn from(k: ProviderKind) -> Self {
+            match k {
+                ProviderKind::Local => SupportedProvider::Local(LocalProvider),
+            }
+        }
+    }
+
+    let provider_kind = ProviderKind::Local;
+    let supported_provider: SupportedProvider = provider_kind.into();
+    assert_eq!(supported_provider, SupportedProvider::Local(LocalProvider));
+}

tests/bin/gman/mod.rs

@@ -0,0 +1 @@
+mod main_tests;

tests/bin/mod.rs

@@ -0,0 +1 @@
+mod gman;