move implementation to internal/ directory (#828)

internal/platformtest/platformtest_exec.go

@@ -0,0 +1,45 @@
+package platformtest
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+
+	"github.com/zrepl/zrepl/internal/util/circlog"
+)
+
+type ex struct {
+	log Logger
+}
+
+func NewEx(log Logger) Execer {
+	return &ex{log}
+}
+
+func (e *ex) RunExpectSuccessNoOutput(ctx context.Context, cmd string, args ...string) error {
+	return e.runNoOutput(true, ctx, cmd, args...)
+}
+
+func (e *ex) RunExpectFailureNoOutput(ctx context.Context, cmd string, args ...string) error {
+	return e.runNoOutput(false, ctx, cmd, args...)
+}
+
+func (e *ex) runNoOutput(expectSuccess bool, ctx context.Context, cmd string, args ...string) error {
+	log := e.log.WithField("command", fmt.Sprintf("%q %q", cmd, args))
+	log.Debug("begin executing")
+	defer log.Debug("done executing")
+	ecmd := exec.CommandContext(ctx, cmd, args...)
+	buf, _ := circlog.NewCircularLog(32 << 10)
+	ecmd.Stdout, ecmd.Stderr = buf, buf
+	err := ecmd.Run()
+	log.WithField("output", buf.String()).Debug("command output")
+	if _, ok := err.(*exec.ExitError); err != nil && !ok {
+		panic(err)
+	}
+	if expectSuccess && err != nil {
+		return fmt.Errorf("expecting no error, got error: %s\n%s", err, buf.String())
+	} else if !expectSuccess && err == nil {
+		return fmt.Errorf("expecting error, got no error")
+	}
+	return nil
+}