Protect against duplicate databases.

src/morethantext/error.rs

@@ -6,6 +6,8 @@ pub enum ErrorCode {
     Undefined(String),
     // Cache
     IDNotFound(String),
+    // Store
+    DuplicateDatabase(String),
 }
 
 impl fmt::Display for ErrorCode {
@@ -13,6 +15,7 @@ impl fmt::Display for ErrorCode {
         match self {
             ErrorCode::Undefined(msg) => write!(f, "{}", msg),
             ErrorCode::IDNotFound(id) => write!(f, "ID '{}' not found", id),
+            ErrorCode::DuplicateDatabase(name) => write!(f, "database '{}' already exists", name),
         }
     }
 }
@@ -37,6 +40,17 @@ mod errorcodes {
             assert_eq!(err.to_string(), format!("ID '{}' not found", item));
         }
     }
+
+    #[test]
+    fn duplicate_database() {
+        for item in ITEMS {
+            let err = ErrorCode::DuplicateDatabase(item.to_string());
+            assert_eq!(
+                err.to_string(),
+                format!("database '{}' already exists", item)
+            );
+        }
+    }
 }
 
 #[derive(Debug)]

src/morethantext/store.rs

@@ -1,4 +1,4 @@
-use super::{Data, Database};
+use super::{Data, Database, ErrorCode, MTTError};
 use std::collections::HashMap;
 
 #[derive(Clone, Debug)]
@@ -13,9 +13,18 @@ impl Store {
         }
     }
 
-    pub fn add(&mut self, name: &str) {
-        let storage = Data::from_data(Database::new());
-        self.data.insert(name.to_string(), storage);
+    pub fn add<S>(&mut self, name: S) -> Result<(), MTTError>
+    where
+        S: Into<String>,
+    {
+        let db_name = name.into();
+        match self.get(&db_name) {
+            Some(_) => Err(MTTError::from_code(ErrorCode::DuplicateDatabase(db_name))),
+            None => {
+                self.data.insert(db_name, Data::from_data(Database::new()));
+                Ok(())
+            }
+        }
     }
 
     pub fn get(&self, name: &str) -> Option<&Data<Database>> {
@@ -29,7 +38,7 @@ impl Store {
 
 #[cfg(test)]
 mod storage {
-    use super::{super::MTTError, *};
+    use super::*;
 
     #[test]
     fn create_new() {
@@ -39,14 +48,40 @@ mod storage {
     }
 
     #[test]
-    fn add_database() {
+    fn add_db_by_str() {
         let mut store = Store::new();
         let name = "Melvin";
-        store.add(name);
+        store.add(name).unwrap();
         let output = store.get(name);
         assert!(output.is_some(), "Get returned none.");
     }
 
+    #[test]
+    fn add_db_by_string() {
+        let mut store = Store::new();
+        let name = "Marvin";
+        store.add(name.to_string()).unwrap();
+        let output = store.get(name);
+        assert!(output.is_some(), "Get returned none.");
+    }
+
+    #[test]
+    fn fail_on_duplicates() -> Result<(), MTTError> {
+        let mut store = Store::new();
+        let name = "Mickie";
+        store.add(name).unwrap();
+        match store.add(name) {
+            Ok(_) => Err(MTTError::new("duplicates should error")),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateDatabase(db_name) => {
+                    assert_eq!(db_name, name);
+                    Ok(())
+                }
+                _ => Err(MTTError::new(format!("{:?} is not DuplicateDatabase", err))),
+            },
+        }
+    }
+
     #[test]
     fn get_bad_database() -> Result<(), MTTError> {
         let store = Store::new();