Repository: ktr0731/evans (go)

Issue:
Desc command Error
Thanks for this awesome tool I've really enjoyed and appreciated it. Maybe I'm doing something wrong but I couldn't figure it out.

## Describe the bug
Desc command can't be executed properly, I've used it manually and I got always an error even if I use the tab key in which Evans assists me with a prompt, results don't change. [Here](https://github.com/cerezo074/GRPC/tree/main/Evans%20Reflection) you can reproduce it easily. 

## To reproduce
Just type command desc with a message name like this **desc LanguageDetectorRequest**

## Expected behavior
Command desc show a table description
## Screenshots
<img width="1105" alt="Screen Shot 2021-02-14 at 8 57 54 PM" src="https://user-images.githubusercontent.com/73249966/107897548-5404ff80-6f07-11eb-892a-514b6ab498bb.png">

## Environment
- OS: Mac OS X 10.15.6 (19G73)
- Terminal: zsh 5.7.1 (x86_64-apple-darwin19.0)
- Evans version: 0.9.3
- `protoc` version: libprotoc 3.14.0
- `protoc` plugin version (if you are using): 

## Additional context
protoc-gen-go-grpc 1.0.1

Pull request description:
fix to work correctly "describe" command against to an empty package
Fixes #367.

Patch:
diff --git a/usecase/get_type_descriptor.go b/usecase/get_type_descriptor.go
index 9318b96..0f56190 100644
--- a/usecase/get_type_descriptor.go
+++ b/usecase/get_type_descriptor.go
@@ -11,9 +11,6 @@ func GetTypeDescriptor(typeName string) (interface{}, error) {
 }
 func (m *dependencyManager) GetTypeDescriptor(typeName string) (interface{}, error) {
 	pkgName := m.state.selectedPackage
-	if pkgName == "" {
-		pkgName = "''"
-	}
 	fqmn := proto.FullyQualifiedMessageName(pkgName, typeName)
 	d, err := m.spec.ResolveSymbol(fqmn)
 	if err != nil {


Test patch:
diff --git a/e2e/cli_test.go b/e2e/cli_test.go
index 236ae04..6206149 100644
--- a/e2e/cli_test.go
+++ b/e2e/cli_test.go
@@ -665,6 +665,12 @@ func TestE2E_CLI(t *testing.T) {
 			args:             "api.SimpleRequest",
 			assertWithGolden: true,
 		},
+		"describe a message descriptor in empty package": {
+			commonFlags:      "--proto testdata/empty_package.proto",
+			cmd:              "desc",
+			args:             "SimpleRequest",
+			assertWithGolden: true,
+		},
 		"invalid symbol": {
 			commonFlags:  "--proto testdata/test.proto,testdata/empty_package.proto",
 			cmd:          "desc",
diff --git a/e2e/repl_test.go b/e2e/repl_test.go
index e53bf12..5b1c174 100644
--- a/e2e/repl_test.go
+++ b/e2e/repl_test.go
@@ -292,6 +292,10 @@ func TestE2E_REPL(t *testing.T) {
 			commonFlags: "--proto testdata/test.proto",
 			input:       []interface{}{"desc SimpleRequest"},
 		},
+		"desc simple message in empty package": {
+			commonFlags: "--proto testdata/empty_package.proto",
+			input:       []interface{}{"desc SimpleRequest"},
+		},
 		"desc a repeated message": {
 			commonFlags: "--proto testdata/test.proto",
 			input:       []interface{}{"desc UnaryRepeatedMessageRequest"},
diff --git a/e2e/testdata/fixtures/teste2e_cli-describe_a_message_descriptor_in_empty_package.golden b/e2e/testdata/fixtures/teste2e_cli-describe_a_message_descriptor_in_empty_package.golden
new file mode 100644
index 0000000..a1c15c0
--- /dev/null
+++ b/e2e/testdata/fixtures/teste2e_cli-describe_a_message_descriptor_in_empty_package.golden
@@ -0,0 +1,4 @@
+SimpleRequest:
+message SimpleRequest {
+  string name = 1;
+}
diff --git a/e2e/testdata/fixtures/teste2e_repl-desc_simple_message_in_empty_package.golden b/e2e/testdata/fixtures/teste2e_repl-desc_simple_message_in_empty_package.golden
new file mode 100644
index 0000000..1b3f653
--- /dev/null
+++ b/e2e/testdata/fixtures/teste2e_repl-desc_simple_message_in_empty_package.golden
@@ -0,0 +1,6 @@
++-------+-------------+----------+
+| FIELD |    TYPE     | REPEATED |
++-------+-------------+----------+
+| name  | TYPE_STRING | false    |
++-------+-------------+----------+
+