tests: add criteria_test.go

This is the start of running tests against the main parts of
ShellAndTest. More to come.

internal/shelltest/criteria_test.go

@@ -0,0 +1,56 @@
+package shelltest
+
+import (
+	"fmt"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTasksRunnerWithError(t *testing.T) {
+	var errCounter = atomic.Int32{}
+	errCount := make(chan int32)
+	defer close(errCount)
+	go func() {
+		// NOTE(mattburchett):
+		// I don't love having to put this sleep here, but in testing, it seems to get data
+		// to quickly and causes the output to return zero. Maybe there's a better way...
+		time.Sleep(1 * time.Second)
+		current := int32(0)
+		fmt.Println("foobar")
+		for {
+			current = <-errCount
+			errCounter.Add(current)
+		}
+	}()
+
+	tasks := []string{"eecho foo", "eecho bar"}
+	err := tasksRunner(tasks, false, errCount)
+	assert.Error(t, err)
+	assert.Equal(t, errCounter.Load(), int32(2))
+}
+
+func TestTasksRunnerWithNoError(t *testing.T) {
+	var errCounter = atomic.Int32{}
+	errCount := make(chan int32)
+	defer close(errCount)
+	go func() {
+		// NOTE(mattburchett):
+		// I don't love having to put this sleep here, but in testing, it seems to get data
+		// too quickly and causes the output to return zero. Maybe there's a better way...
+		time.Sleep(1 * time.Second)
+		current := int32(0)
+		fmt.Println("foobar")
+		for {
+			current = <-errCount
+			errCounter.Add(current)
+		}
+	}()
+
+	tasks := []string{"echo foo", "echo bar"}
+	err := tasksRunner(tasks, false, errCount)
+	assert.NoError(t, err)
+	assert.Equal(t, errCounter.Load(), int32(0))
+}