Add unit tests for Pipeline struct

Refs: #406

internal/osbuild/osbuild_test.go

@@ -0,0 +1,59 @@
+// Package osbuild provides primitives for representing and (un)marshalling
+// OSBuild types.
+package osbuild
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPipeline_SetBuild(t *testing.T) {
+	expectedPipeline := &Pipeline{
+		Build: &Build{
+			Pipeline: &Pipeline{},
+			Runner:   "org.osbuild.fedora31",
+		},
+	}
+	actualPipeline := &Pipeline{}
+	actualPipeline.SetBuild(&Pipeline{}, "org.osbuild.fedora31")
+	assert.Equal(t, expectedPipeline, actualPipeline)
+}
+
+func TestPipeline_AddStage(t *testing.T) {
+	expectedPipeline := &Pipeline{
+		Build: &Build{
+			Pipeline: &Pipeline{},
+			Runner:   "org.osbuild.fedora31",
+		},
+		Stages: []*Stage{
+			{
+				Name: "org.osbuild.rpm",
+			},
+		},
+	}
+	actualPipeline := &Pipeline{
+		Build: &Build{
+			Pipeline: &Pipeline{},
+			Runner:   "org.osbuild.fedora31",
+		},
+	}
+	actualPipeline.AddStage(&Stage{
+		Name: "org.osbuild.rpm",
+	})
+	assert.Equal(t, expectedPipeline, actualPipeline)
+	assert.Equal(t, 1, len(actualPipeline.Stages))
+}
+
+func TestPipeline_SetAssembler(t *testing.T) {
+	expectedPipeline := &Pipeline{
+		Assembler: &Assembler{
+			Name: "org.osbuild.testassembler",
+		},
+	}
+	actualPipeline := &Pipeline{}
+	actualPipeline.SetAssembler(&Assembler{
+		Name: "org.osbuild.testassembler",
+	})
+	assert.Equal(t, expectedPipeline, actualPipeline)
+}