fix: schema validation for job if functions (#2446)

* fix: schema validation for job if functions

* Add Tests

* Update pkg/schema/schema.go

Co-authored-by: Josh Soref <2119212+jsoref@users.noreply.github.com>

* Update pkg/schema/schema.go

---------

Co-authored-by: Josh Soref <2119212+jsoref@users.noreply.github.com>

pkg/schema/schema_test.go

@@ -0,0 +1,92 @@
+package schema
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v3"
+)
+
+func TestAdditionalFunctions(t *testing.T) {
+	var node yaml.Node
+	err := yaml.Unmarshal([]byte(`
+on: push
+jobs:
+  job-with-condition:
+    runs-on: self-hosted
+    if: success() || success('joba', 'jobb') || failure() || failure('joba', 'jobb') || always() || cancelled()
+    steps:
+    - run: exit 0
+`), &node)
+	if !assert.NoError(t, err) {
+		return
+	}
+	err = (&Node{
+		Definition: "workflow-root-strict",
+		Schema:     GetWorkflowSchema(),
+	}).UnmarshalYAML(&node)
+	assert.NoError(t, err)
+}
+
+func TestAdditionalFunctionsFailure(t *testing.T) {
+	var node yaml.Node
+	err := yaml.Unmarshal([]byte(`
+on: push
+jobs:
+  job-with-condition:
+    runs-on: self-hosted
+    if: success() || success('joba', 'jobb') || failure() || failure('joba', 'jobb') || always('error')
+    steps:
+    - run: exit 0
+`), &node)
+	if !assert.NoError(t, err) {
+		return
+	}
+	err = (&Node{
+		Definition: "workflow-root-strict",
+		Schema:     GetWorkflowSchema(),
+	}).UnmarshalYAML(&node)
+	assert.Error(t, err)
+}
+
+func TestAdditionalFunctionsSteps(t *testing.T) {
+	var node yaml.Node
+	err := yaml.Unmarshal([]byte(`
+on: push
+jobs:
+  job-with-condition:
+    runs-on: self-hosted
+    steps:
+    - run: exit 0
+      if: success() || failure() || always()
+`), &node)
+	if !assert.NoError(t, err) {
+		return
+	}
+	err = (&Node{
+		Definition: "workflow-root-strict",
+		Schema:     GetWorkflowSchema(),
+	}).UnmarshalYAML(&node)
+	assert.NoError(t, err)
+}
+
+func TestAdditionalFunctionsStepsExprSyntax(t *testing.T) {
+	var node yaml.Node
+	err := yaml.Unmarshal([]byte(`
+on: push
+jobs:
+  job-with-condition:
+    runs-on: self-hosted
+    steps:
+    - run: exit 0
+      if: ${{ success() || failure() || always() }}
+`), &node)
+	if !assert.NoError(t, err) {
+		return
+	}
+	err = (&Node{
+		Definition: "workflow-root-strict",
+		Schema:     GetWorkflowSchema(),
+	}).UnmarshalYAML(&node)
+	assert.NoError(t, err)
+}