Remove all shell presubmits (#3631)

This ports the shell presubmit to Go and makes them better; esp the
Errorf/Logf/Fatalf one because it actually parses the code and works of
the AST.

These error will now show up in the travis/circle CI runs where they
belong.

Signed-off-by: Miek Gieben <miek@miek.nl>

test/presubmit_test.go

@@ -5,6 +5,9 @@ package test
 import (
 	"bufio"
 	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
 	"os"
 	"path/filepath"
 	"strings"
@@ -75,3 +78,133 @@ func hasHyphen(path string, info os.FileInfo, _ error) error {
 
 	return nil
 }
+
+// Test if error messages start with an upper case.
+func TestLowercaseLog(t *testing.T) {
+	err := filepath.Walk("..", hasLowercase)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func hasLowercase(path string, info os.FileInfo, _ error) error {
+	// only for regular files, not starting with a . and those that are go files.
+	if !info.Mode().IsRegular() {
+		return nil
+	}
+	if strings.HasPrefix(path, "../.") {
+		return nil
+	}
+	if !strings.HasSuffix(path, "_test.go") {
+		return nil
+	}
+
+	fs := token.NewFileSet()
+	f, err := parser.ParseFile(fs, path, nil, parser.AllErrors)
+	if err != nil {
+		return err
+	}
+	l := &logfmt{}
+	ast.Walk(l, f)
+	if l.err != nil {
+		return l.err
+	}
+	return nil
+}
+
+type logfmt struct {
+	err error
+}
+
+func (l logfmt) Visit(n ast.Node) ast.Visitor {
+	if n == nil {
+		return nil
+	}
+	ce, ok := n.(*ast.CallExpr)
+	if !ok {
+		return l
+	}
+	se, ok := ce.Fun.(*ast.SelectorExpr)
+	if !ok {
+		return l
+	}
+	id, ok := se.X.(*ast.Ident)
+	if !ok {
+		return l
+	}
+	if id.Name != "t" { //t *testing.T
+		return l
+	}
+
+	switch se.Sel.Name {
+	case "Errorf":
+	case "Logf":
+	case "Log":
+	case "Fatalf":
+	case "Fatal":
+	default:
+		return l
+	}
+	// Check first arg, that should have basic lit with capital
+	if len(ce.Args) < 1 {
+		return l
+	}
+	bl, ok := ce.Args[0].(*ast.BasicLit)
+	if !ok {
+		return l
+	}
+	if bl.Kind != token.STRING {
+		return l
+	}
+	if strings.HasPrefix(bl.Value, "\"%s") || strings.HasPrefix(bl.Value, "\"%d") {
+		return l
+	}
+	if strings.HasPrefix(bl.Value, "\"%v") || strings.HasPrefix(bl.Value, "\"%+v") {
+		return l
+	}
+	for i, u := range bl.Value {
+		// disregard "
+		if i == 1 && !unicode.IsUpper(u) {
+			l.err = fmt.Errorf("test error message %s doesn't start with an uppercase", bl.Value)
+			return nil
+		}
+		if i == 1 {
+			break
+		}
+	}
+	return l
+}
+
+func TestImportTesting(t *testing.T) {
+	err := filepath.Walk("..", hasImportTesting)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func hasImportTesting(path string, info os.FileInfo, _ error) error {
+	// only for regular files, not starting with a . and those that are go files.
+	if !info.Mode().IsRegular() {
+		return nil
+	}
+	if strings.HasPrefix(path, "../.") {
+		return nil
+	}
+	if strings.HasSuffix(path, "_test.go") {
+		return nil
+	}
+
+	if strings.HasSuffix(path, ".go") {
+		fs := token.NewFileSet()
+		f, err := parser.ParseFile(fs, path, nil, parser.AllErrors)
+		if err != nil {
+			return err
+		}
+		for _, im := range f.Imports {
+			if im.Path.Value == `"testing"` {
+				return fmt.Errorf("file %q is importing %q", path, "testing")
+			}
+		}
+	}
+	return nil
+}