Reading files!

- File.close()
- File.open()
- File.read()
- file.readBytes()

And a few other little methods. Still lots more work to do, but it's a
start.

test/io/file/close.wren

@@ -0,0 +1,19 @@
+import "io" for File
+import "scheduler" for Scheduler
+
+// See also: is_open.wren.
+
+var file = File.open("test/io/file/close.wren")
+
+System.print(file.close()) // expect: null
+
+// Can call multiple times.
+file.close()
+
+// If already closed, returns synchronously.
+Scheduler.add {
+  System.print("does not print")
+}
+
+file.close()
+System.print("sync") // expect: sync

test/io/file/descriptor.wren

@@ -0,0 +1,11 @@
+import "io" for File
+
+var file = File.open("test/io/file/descriptor.wren")
+
+// We can't test for a specific value since it's up to the OS, but it should be
+// a positive number.
+System.print(file.descriptor is Num) // expect: true
+System.print(file.descriptor > 0) // expect: true
+
+file.close()
+System.print(file.descriptor) // expect: -1

test/io/file/file.txt

@@ -0,0 +1 @@
+this is a text file

test/io/file/is_open.wren

@@ -0,0 +1,6 @@
+import "io" for File
+
+var file = File.open("test/io/file/is_open.wren")
+System.print(file.isOpen) // expect: true
+file.close()
+System.print(file.isOpen) // expect: false

test/io/file/open.wren

@@ -0,0 +1,5 @@
+import "io" for File
+
+var file = File.open("test/io/file/open.wren")
+System.print(file is File) // expect: true
+System.print(file.isOpen) // expect: true

test/io/file/open_block.wren

@@ -0,0 +1,16 @@
+import "io" for File
+
+var stash
+File.open("test/io/file/open_block.wren") {|file|
+  System.print(file is File) // expect: true
+  System.print(file.isOpen) // expect: true
+  stash = file
+}
+
+// Closes after block.
+System.print(stash.isOpen) // expect: false
+
+// Returns null.
+System.print(File.open("test/io/file/open_block.wren") {|file|}) // expect: null
+
+// TODO: Test a fiber aborting inside the block.

test/io/file/open_block_nonexistent.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.open("nonexistent") {|file|} // expect runtime error: no such file or directory

test/io/file/open_block_wrong_block_type.wren

@@ -0,0 +1,4 @@
+import "io" for File
+
+File.open("test/io/file/open_block_wrong_block_type.wren",
+    "no callable") // expect runtime error: String does not implement 'call(_)'.

test/io/file/open_block_wrong_path_type.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.open(123) {|file|} // expect runtime error: Path must be a string.

test/io/file/open_nonexistent.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.open("nonexistent") // expect runtime error: no such file or directory

test/io/file/open_wrong_arg_type.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.open(123) // expect runtime error: Path must be a string.

test/io/file/read.wren

@@ -0,0 +1,8 @@
+import "io" for File
+
+var text = File.read("test/io/file/file.txt")
+System.print(text) // expect: this is a text file
+System.print(text.count) // expect: 19
+
+// TODO: A file containing line endings.
+// TODO: A file containing null bytes.

test/io/file/read_bytes.wren

@@ -0,0 +1,13 @@
+import "io" for File
+
+var file = File.open("test/io/file/file.txt")
+
+System.print(file.readBytes(3)) // expect: thi
+
+// Always reads from the beginning.
+System.print(file.readBytes(7)) // expect: this is
+
+// Allows zero.
+System.print(file.readBytes(0).bytes.count) // expect: 0
+
+file.close()

test/io/file/read_bytes_after_close.wren

@@ -0,0 +1,6 @@
+import "io" for File
+
+var file = File.open("test/io/file/file.txt")
+file.close()
+
+file.readBytes(3) // expect runtime error: File is not open.

test/io/file/read_bytes_count_not_num.wren

@@ -0,0 +1,4 @@
+import "io" for File
+
+var file = File.open("test/io/file/file.txt")
+file.readBytes("not num") // expect runtime error: Count must be an integer.

test/io/file/read_bytes_negative.wren

@@ -0,0 +1,4 @@
+import "io" for File
+
+var file = File.open("test/io/file/file.txt")
+file.readBytes(-1) // expect runtime error: Count cannot be negative.

test/io/file/read_bytes_not_integer.wren

@@ -0,0 +1,4 @@
+import "io" for File
+
+var file = File.open("test/io/file/file.txt")
+file.readBytes(1.2) // expect runtime error: Count must be an integer.

test/io/file/read_nonexistent.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.read("nonexistent") // expect runtime error: no such file or directory

test/io/file/read_wrong_arg_type.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.read(123) // expect runtime error: Path must be a string.

test/io/file/size.wren

@@ -1,7 +1,7 @@
 import "io" for File
 import "scheduler" for Scheduler
 
-System.print(File.size("test/io/file/size.wren")) // expect: 401
+System.print(File.size("test/io/file/size.wren")) // expect: 270
 
 // Runs asynchronously.
 Scheduler.add {
@@ -10,9 +10,4 @@ Scheduler.add {
 
 System.print(File.size("test/io/file/size.wren"))
 // expect: async
-// expect: 401
-
-var error = Fiber.new {
-  System.print(File.size("nonexistent"))
-}.try()
-System.print(error) // expect: no such file or directory
+// expect: 270

test/io/file/size_after_close.wren

@@ -0,0 +1,6 @@
+import "io" for File
+
+var file = File.open("test/io/file/file.txt")
+file.close()
+
+file.size // expect runtime error: File is not open.

test/io/file/size_nonexistent.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.size("nonexistent") // expect runtime error: no such file or directory