Make envs available in if conditionals (#225)

* Ignore .idea

* Add Env to the RunContext vm so we can Evaluate and Interpolate `env.xx`

* Make EvalBool support expressions more in line with the github runner

* Turns out Boolean(value) is what github is doing after all

* Add test for github context as well

act/runner/run_context_test.go

@@ -0,0 +1,107 @@
+package runner
+
+import (
+	"github.com/nektos/act/pkg/model"
+	a "github.com/stretchr/testify/assert"
+	"testing"
+
+	"github.com/sirupsen/logrus/hooks/test"
+)
+
+func TestRunContext_EvalBool(t *testing.T) {
+	hook := test.NewGlobal()
+	assert := a.New(t)
+	rc := &RunContext{
+		Config: &Config{
+			Workdir: ".",
+		},
+		Env: map[string]string{
+			"TRUE":  "true",
+			"FALSE": "false",
+			"SOME_TEXT": "text",
+		},
+		Run: &model.Run{
+			JobID: "job1",
+			Workflow: &model.Workflow{
+				Name: "test-workflow",
+				Jobs: map[string]*model.Job{
+					"job1": {
+						Strategy: &model.Strategy{
+							Matrix: map[string][]interface{}{
+								"os":  {"Linux", "Windows"},
+								"foo": {"bar", "baz"},
+							},
+						},
+					},
+				},
+			},
+		},
+		Matrix: map[string]interface{}{
+			"os":  "Linux",
+			"foo": "bar",
+		},
+		StepResults: map[string]*stepResult{
+			"id1": {
+				Outputs: map[string]string{
+					"foo": "bar",
+				},
+				Success: true,
+			},
+		},
+	}
+	rc.ExprEval = rc.NewExpressionEvaluator()
+
+	tables := []struct {
+		in      string
+		out     bool
+	}{
+		// The basic ones
+		{"true", true},
+		{"false", false},
+		{"1 !== 0", true},
+		{"1 !== 1", false},
+		{"1 == 0", false},
+		{"1 == 1", true},
+		{"1 > 2", false},
+		{"1 < 2", true},
+		{"success()", true},
+		{"failure()", false},
+		// And or
+		{"true && false", false},
+		{"true && 1 < 2", true},
+		{"false || 1 < 2", true},
+		{"false || false", false},
+		// None boolable
+		{"env.SOME_TEXT", true},
+		{"env.UNKNOWN == 'true'", false},
+		{"env.UNKNOWN", false},
+		// Inline expressions
+		{"env.TRUE == 'true'", true},
+		{"env.FALSE == 'true'", false},
+		{"${{env.TRUE == 'true'}}", true},
+		{"${{env.FALSE == 'true'}}", false},
+		{"${{env.FALSE == 'false'}}", true},
+		// All together now
+		{"false || env.TRUE == 'true'", true},
+		{"true || env.FALSE == 'true'", true},
+		{"true && env.TRUE == 'true'", true},
+		{"false && env.TRUE == 'true'", false},
+		{"env.FALSE == 'true' && env.TRUE == 'true'", false},
+		{"env.FALSE == 'true' && true", false},
+		{"${{env.FALSE == 'true'}} && true", false},
+		// Check github context
+		{"github.actor == 'nektos/act'", true},
+		{"github.actor == 'unknown'", false},
+	}
+
+	for _, table := range tables {
+		table := table
+		t.Run(table.in, func(t *testing.T) {
+			defer hook.Reset()
+			b := rc.EvalBool(table.in)
+
+			assert.Equal(table.out, b, table.in)
+			assert.Empty(hook.LastEntry(), table.in)
+		})
+	}
+}