TOML to JSON cli tool (#85)

* Implement tomljson
* Add note about tools in README

cmd/tomljson/main_test.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"testing"
+	"strings"
+	"bytes"
+	"os"
+	"io/ioutil"
+)
+
+func expectBufferEquality(t *testing.T, name string, buffer *bytes.Buffer, expected string) {
+	output := buffer.String()
+	if output != expected {
+		t.Errorf("incorrect %s:\n%s\n\nexpected %s:\n%s", name, output, name, expected)
+		t.Log([]rune(output))
+		t.Log([]rune(expected))
+	}
+}
+
+func expectProcessMainResults(t *testing.T, input string, args []string, exitCode int, expectedOutput string, expectedError string) {
+	inputReader := strings.NewReader(input)
+	outputBuffer := new(bytes.Buffer)
+	errorBuffer := new(bytes.Buffer)
+
+	returnCode := processMain(args, inputReader, outputBuffer, errorBuffer)
+
+	expectBufferEquality(t, "output", outputBuffer, expectedOutput)
+	expectBufferEquality(t, "error", errorBuffer, expectedError)
+
+	if returnCode != exitCode {
+		t.Error("incorrect return code:", returnCode, "expected", exitCode)
+	}
+}
+
+
+func TestProcessMainReadFromStdin(t *testing.T) {
+	input := `
+		[mytoml]
+		a = 42`
+	expectedOutput := `{
+  "mytoml": {
+    "a": 42
+  }
+}
+`
+	expectedError := ``
+	expectedExitCode := 0
+
+	expectProcessMainResults(t, input, []string{}, expectedExitCode, expectedOutput, expectedError)
+}
+
+func TestProcessMainReadFromFile(t *testing.T) {
+	input := `
+		[mytoml]
+		a = 42`
+
+
+	tmpfile, err := ioutil.TempFile("", "example.toml")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := tmpfile.Write([]byte(input)); err != nil {
+		t.Fatal(err)
+	}
+
+	defer os.Remove(tmpfile.Name())
+
+	expectedOutput := `{
+  "mytoml": {
+    "a": 42
+  }
+}
+`
+	expectedError := ``
+	expectedExitCode := 0
+
+	expectProcessMainResults(t, ``, []string{tmpfile.Name()}, expectedExitCode, expectedOutput, expectedError)
+}
+
+func TestProcessMainReadFromMissingFile(t *testing.T) {
+	expectedError := `open /this/file/does/not/exist: no such file or directory
+`
+	expectProcessMainResults(t, ``, []string{"/this/file/does/not/exist"}, -1, ``, expectedError)
+}