diff --git a/Sources/Algebra.swift b/Sources/Algebra.swift
index 75b883a..8eb89c8 100644
--- a/Sources/Algebra.swift
+++ b/Sources/Algebra.swift
@@ -16,15 +16,18 @@
 
 import Foundation
 	
+/// Data Structure/Schema representing an entry in a fish history file.
 struct FishHistoryEntry: Equatable {
     let cmd: String
     let when: Int
     let paths: [String]
-    
+   
+    /// Converts time to Date object
     func getDate() -> Date {
         Date(timeIntervalSince1970: TimeInterval(when))
     }
-    
+   
+    /// Converts structure back to list of strings as expected in a fish history file.
     func writeEntry() -> [String] {
         var output: [String] = []
         
diff --git a/Sources/FileHelpers.swift b/Sources/FileHelpers.swift
index 42e0a94..b00adfc 100644
--- a/Sources/FileHelpers.swift
+++ b/Sources/FileHelpers.swift
@@ -18,6 +18,12 @@
 import Foundation
 
 
+/// Gets the full file path to a given file.
+///
+/// - Parameters
+///     - pathStr: The file path to a file.
+///
+/// - Returns: A Valid file URL or None if invalid.
 func getPath(_ pathStr: String) -> URL? {
     let userHomeDirectory = FileManager.default.homeDirectoryForCurrentUser.path
     var filePath: String = pathStr
diff --git a/Sources/Parser.swift b/Sources/Parser.swift
index d1b5bf7..2c04349 100644
--- a/Sources/Parser.swift
+++ b/Sources/Parser.swift
@@ -18,6 +18,18 @@
 import Foundation
 
 
+/// Make a backup of the fish history.
+///
+/// ```
+///The copied files name will have _copy appended to the filename before the file extension.
+///For example:
+///   if the file was example.txt the copied file will be example_copy.txt
+/// ```
+///
+/// - Parameters
+///     - path: The file path to the fish history file.
+///
+/// - Returns: true if backup copy successful, false if not.
 func backupHistory(_ path: String) -> Bool {
     let fileManager = FileManager.default
         
@@ -46,6 +58,14 @@ func backupHistory(_ path: String) -> Bool {
 }
 
 
+/// Write fish history to file.
+///
+/// - Parameters
+///     - path: The file path to the fish history file.
+///     - history: History list to write to file.
+///     - backup: Should the current history file be backed up first boolean.
+///
+/// - Returns: true if writing to file copy successful, false if not.
 func writeFishHistory(to path: String, history: [FishHistoryEntry], backup: Bool = true) -> Bool {
     var output = ""
     
@@ -75,6 +95,12 @@ func writeFishHistory(to path: String, history: [FishHistoryEntry], backup: Bool
     }
 }
 
+/// Parse the fish history file.
+///
+/// - Parameters
+///     - filePath: The file path to the fish history file.
+///
+/// - Returns: List of ``FishHistoryEntry`` entries from history file.
 func parseFishHistory(from filePath: String) -> [FishHistoryEntry]? {
     guard let fileContents = try? String(contentsOfFile: filePath) else {
         print("Failed to open file.")
@@ -113,6 +139,14 @@ func parseFishHistory(from filePath: String) -> [FishHistoryEntry]? {
     return result.entries
 }
 
+/// Merge two given ``FishHistoryEntry`` lists into one list.
+///
+/// - Parameters
+///     - left: The file path to the first fish history file.
+///     - right: The file path to the second fish history file.
+///     - removeDuplicates: if true, remove any duplicates found after merging the two lists.
+///
+/// - Returns: Single list of ``FishHistoryEntry`` entries.
 func mergeFishHistory(_ left: [FishHistoryEntry], _ right: [FishHistoryEntry], removeDuplicates: Bool = false) -> [FishHistoryEntry] {
     
     let merged = left + right
@@ -127,5 +161,4 @@ func mergeFishHistory(_ left: [FishHistoryEntry], _ right: [FishHistoryEntry], r
     } else {
         return merged
     }
-    
 }
diff --git a/Tests/FisheeTests.swift b/Tests/FisheeTests.swift
new file mode 100644
index 0000000..e69de29
diff --git a/Tests/TestPlan.xctestplan b/Tests/TestPlan.xctestplan
new file mode 100644
index 0000000..ddd7728
--- /dev/null
+++ b/Tests/TestPlan.xctestplan
@@ -0,0 +1,18 @@
+{
+  "configurations" : [
+    {
+      "id" : "1485A2F9-7AD1-4B2E-9F5B-CADD587FC5F6",
+      "name" : "Configuration 1",
+      "options" : {
+
+      }
+    }
+  ],
+  "defaultOptions" : {
+    "testTimeoutsEnabled" : true
+  },
+  "testTargets" : [
+
+  ],
+  "version" : 1
+}