Add Checks to copy.lua

src/main/resources/assets/computercraft/lua/rom/programs/copy.lua

@@ -15,6 +15,10 @@ if #tFiles > 0 then
         elseif #tFiles == 1 then
             if fs.exists( sDest ) then
                  printError( "Destination exists" )
+            elseif fs.isReadOnly( sDest ) then
+                printError( "Destination is read-only" )
+            elseif fs.getFreeSpace( sDest ) < fs.getSize( sFile ) then
+                printError( "Not enough space" )
             else
                  fs.copy( sFile, sDest )
             end

src/test/resources/test-rom/spec/programs/copy_spec.lua

@@ -0,0 +1,40 @@
+local capture = require "test_helpers".capture_program
+
+describe("The copy program", function()
+    local function touch(file)
+        io.open(file, "w"):close()
+    end
+
+    it("copies a file", function()
+        touch("/test-files/copy/a.txt")
+
+        shell.run("copy /test-files/copy/a.txt /test-files/copy/b.txt")
+
+        expect(fs.exists("/test-files/copy/a.txt")):eq(true)
+        expect(fs.exists("/test-files/copy/b.txt")):eq(true)
+    end)
+
+    it("fails when copying a non-existent file", function()
+        expect(capture(stub, "copy nothing destination"))
+            :matches { ok = true, output = "", error = "No matching files\n" }
+    end)
+
+    it("fails when overwriting an existing file", function()
+        touch("/test-files/copy/c.txt")
+
+        expect(capture(stub, "copy /test-files/copy/c.txt /test-files/copy/c.txt"))
+            :matches { ok = true, output = "", error = "Destination exists\n" }
+    end)
+
+    it("fails when copying into read-only locations", function()
+        touch("/test-files/copy/d.txt")
+
+        expect(capture(stub, "copy /test-files/copy/d.txt /rom/test.txt"))
+            :matches { ok = true, output = "", error = "Destination is read-only\n" }
+    end)
+
+    it("displays the usage when given no arguments", function()
+        expect(capture(stub, "copy"))
+            :matches { ok = true, output = "Usage: cp <source> <destination>\n", error = "" }
+    end)
+end)