correct exit code assertion in exec plugin

The constructor for assertions in the exec plugin was incorrectly
setting the expected exit code equal to the exit code it received from
the test spec, resulting in script or command executions returning
non-0 exit codes from causing a test.FailNow().

Signed-off-by: Jay Pipes <[email protected]>

plugin/exec/assertions.go

@@ -166,9 +166,13 @@ func newAssertions(
 	outPipe *bytes.Buffer,
 	errPipe *bytes.Buffer,
 ) api.Assertions {
+	expExitCode := 0
+	if e != nil {
+		expExitCode = e.ExitCode
+	}
 	a := &assertions{
 		failures:    []error{},
-		expExitCode: exitCode,
+		expExitCode: expExitCode,
 		exitCode:    exitCode,
 	}
 	if e != nil {

plugin/exec/eval_test.go

@@ -9,6 +9,7 @@ import (
 	"bytes"
 	"context"
 	"flag"
+	"fmt"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -71,6 +72,52 @@ func TestExitCode(t *testing.T) {
 	require.Nil(err)
 }
 
+func TestFailExecExitCodeNotSpecified(t *testing.T) {
+	if !*failFlag {
+		t.Skip("skipping without -fail flag")
+	}
+	require := require.New(t)
+
+	fp := filepath.Join("testdata", "ls-fail-no-exit-code.yaml")
+	f, err := os.Open(fp)
+	require.Nil(err)
+
+	s, err := scenario.FromReader(
+		f,
+		scenario.WithPath(fp),
+	)
+	require.Nil(err)
+	require.NotNil(s)
+
+	ctx := gdtcontext.New(gdtcontext.WithDebug())
+	err = s.Run(ctx, t)
+	require.Nil(err)
+}
+
+func TestExecFailExitCodeNotSpecified(t *testing.T) {
+	require := require.New(t)
+	target := os.Args[0]
+	failArgs := []string{
+		"-test.v",
+		"-test.run=FailExecExitCodeNotSpecified",
+		"-fail",
+	}
+	outerr, err := exec.Command(target, failArgs...).CombinedOutput()
+
+	// The test should have failed...
+	require.NotNil(err)
+	debugout := string(outerr)
+	ec := 2
+	// Yay, different exit codes for the same not found error...
+	if runtime.GOOS == "darwin" {
+		ec = 1
+	}
+	msg := fmt.Sprintf(
+		"assertion failed: not equal: expected 0 but got %d", ec,
+	)
+	require.Contains(debugout, msg)
+}
+
 func TestShellList(t *testing.T) {
 	require := require.New(t)
 

plugin/exec/testdata/ls-fail-no-exit-code.yaml

@@ -0,0 +1,4 @@
+name: ls-fail-no-exit-code
+description: a scenario that runs the `ls` command with a non-0 exit code and no assertion on exit code
+tests:
+  - exec: ls /this/dir/does/not/exist