simplify testing

testing/assert/assert.go

@@ -0,0 +1,70 @@
+package assert
+
+import (
+	"bytes"
+	"fmt"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func On(t *testing.T) *Assert {
+	return &Assert{
+		t: t,
+	}
+}
+
+type Assert struct {
+	t *testing.T
+}
+
+func (this *Assert) Fail(message string) {
+	fmt.Println(decorate(message))
+	this.t.Fail()
+}
+
+func getCaller() (string, int) {
+	stackLevel := 3
+	for {
+		_, file, line, ok := runtime.Caller(stackLevel)
+		if strings.Contains(file, "assert") {
+			stackLevel++
+		} else {
+			if ok {
+				// Truncate file name at last file name separator.
+				if index := strings.LastIndex(file, "/"); index >= 0 {
+					file = file[index+1:]
+				} else if index = strings.LastIndex(file, "\\"); index >= 0 {
+					file = file[index+1:]
+				}
+			} else {
+				file = "???"
+				line = 1
+			}
+			return file, line
+		}
+	}
+}
+
+// decorate prefixes the string with the file and line of the call site
+// and inserts the final newline if needed and indentation tabs for formatting.
+func decorate(s string) string {
+	file, line := getCaller()
+	buf := new(bytes.Buffer)
+	// Every line is indented at least one tab.
+	buf.WriteString("  ")
+	fmt.Fprintf(buf, "%s:%d: ", file, line)
+	lines := strings.Split(s, "\n")
+	if l := len(lines); l > 1 && lines[l-1] == "" {
+		lines = lines[:l-1]
+	}
+	for i, line := range lines {
+		if i > 0 {
+			// Second and subsequent lines are indented an extra tab.
+			buf.WriteString("\n\t\t")
+		}
+		buf.WriteString(line)
+	}
+	buf.WriteByte('\n')
+	return buf.String()
+}