Merge pull request #88 from Hombre-x/readlines-change

Change `readLines` behaviour when reading an empty last newline

core/src/main/scala/io/chrisdavenport/shellfish/FilesOs.scala

@@ -81,15 +81,20 @@ object FilesOs {
 
   /**
    * Reads the contents of the file at the path using UTF-8 decoding and returns
-   * it line by line as a List of Strings.
+   * it line by line as a List of Strings. It will ignore any empty characters
+   * after the last newline (similar to `wc -l`).
    *
    * @param path
    *   The path to read from
    * @return
    *   The file loaded in memory as a collection of lines of Strings
    */
   def readLines(path: Path): IO[List[String]] =
-    files.readUtf8Lines(path).compile.toList
+    files
+      .readUtf8Lines(path)
+      .dropLastIf(_.isEmpty)
+      .compile
+      .toList
 
   /**
    * Reads the contents of the file and deserializes its contents as `A` using

core/src/main/scala/io/chrisdavenport/shellfish/syntax/path/package.scala

@@ -75,7 +75,8 @@ package object path {
 
     /**
      * Reads the contents of the file at the path using UTF-8 decoding and
-     * returns it line by line as a List of Strings.
+     * returns it line by line as a List of Strings. It will ignore any empty
+     * characters after the last newline (similar to `wc -l`).
      *
      * @param path
      *   The path to read from

core/src/test/scala/io/chrisdavenport/shellfish/FileOsSpec.scala

@@ -80,7 +80,8 @@ object FileOsSpec extends SimpleIOSuite with Checkers {
           sizeBefore <- path.readLines.map(_.size)
           _          <- path.appendLine("Im a last line!")
           sizeAfter  <- path.readLines.map(_.size)
-        } yield expect(sizeBefore + 1 == sizeAfter)
+        } yield expect(sizeBefore + 2 == sizeAfter)
+        // That is, one new line of the appendLine and, one newline character of the writeLines method
       }
     }
   }
@@ -322,7 +323,7 @@ object FileOsSpec extends SimpleIOSuite with Checkers {
     }
   }
 
-  // Warning: Platform dependent test; this may fail on some operating systems
+  // Warning: Platform-dependent test; this may fail on some operating systems
   test("We should be able to get the file permissions in POSIX systems") {
 
     val permissionsGenerator: Gen[PosixPermissions] =
@@ -343,4 +344,20 @@ object FileOsSpec extends SimpleIOSuite with Checkers {
     }
   }
 
+  test(
+    "Writing lines should return a list with the same length when reading them"
+  ) {
+    val contentGenerator: Gen[List[String]] =
+      Gen.size.flatMap(size => Gen.listOfN(size, Gen.alphaNumStr))
+
+    forall(contentGenerator) { contentsList =>
+      withTempFile { path =>
+        for {
+          _       <- path.writeLines(contentsList)
+          readlns <- path.readLines
+        } yield expect(contentsList.length == readlns.length)
+      }
+    }
+  }
+
 }