feat(main): support modifying built platformsv0.1.0

Bakelite now accepts a platform modification string vita the -platform
flag. This string format for adding and removing the built platforms,
including removing the default platforms entirely. It is processed left
to right.

  bakelite -platform '-windows +linux/s390x' [packages]

Would now build [packages] for all of the default platforms, except for
Windows, and also build for the linux/s390x platform.

  bakelite -platform '- +linux +darwin' [packages]

Would now build [packages] for the default platforms of only the Linux
and Darwin operating systems.

The platform modification string is parsed and turned into calls to
a structure following the builder pattern.

As the user can now modify the built platforms, Bakelite now exits with
a non-zero exit code if any of the platforms fail to build.

Change-Id: Iade51e17bbfda4e916394343a5f8cb3208f2b160

1 files changed, 117 insertions, 0 deletions

diff --git a/platforms_test.go b/platforms_test.go
new file mode 100644
index 0000000..b2fcacc
--- /dev/null
+++ b/platforms_test.go
@@ -0,0 +1,117 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+)
+
+func ExampleNewPlatformBuilder() {
+	plb, _ := NewPlatformBuilder()
+
+	plb = plb.
+		WithOS(OS("windows")).
+		WithoutPlatform(Platform{OS("windows"), Arch("amd64")}).
+		WithPlatform(Platform{OS("plan9"), Arch("amd64")})
+
+	pl := plb.Build()
+	sort.SliceStable(pl, func(i, j int) bool {
+		return lessPlatforms(pl[i], pl[j])
+	})
+
+	fmt.Println(pl)
+
+	// Output:
+	// [{plan9 amd64} {windows 386}]
+}
+
+func TestWithOS(t *testing.T) {
+	plb, _ := NewPlatformBuilder()
+
+	plb = plb.WithOS(OS("windows"))
+
+	pl := plb.Build()
+	expected := defaultWindows()
+
+	if diff := cmp.Diff(expected, pl, cmpopts.SortSlices(lessPlatforms)); diff != "" {
+		t.Errorf("manifest differs. (-got +want):\n%s", diff)
+	}
+}
+
+func TestWithoutOS(t *testing.T) {
+	plb, _ := NewPlatformBuilder()
+
+	plb = plb.
+		WithPlatform(
+			Platform{OS("windows"), Arch("amd64")},
+		).
+		WithPlatform(
+			Platform{OS("plan9"), Arch("amd64")},
+		).
+		WithoutOS(OS("windows"))
+
+	pl := plb.Build()
+	expected := []Platform{{OS("plan9"), Arch("amd64")}}
+
+	if diff := cmp.Diff(expected, pl, cmpopts.SortSlices(lessPlatforms)); diff != "" {
+		t.Errorf("manifest differs. (-got +want):\n%s", diff)
+	}
+}
+
+func TestWithPlatform(t *testing.T) {
+	plb, _ := NewPlatformBuilder()
+
+	plb = plb.WithPlatform(Platform{OS("windows"), Arch("arm64")})
+
+	pl := plb.Build()
+	expected := []Platform{{OS("windows"), Arch("arm64")}}
+
+	if diff := cmp.Diff(expected, pl, cmpopts.SortSlices(lessPlatforms)); diff != "" {
+		t.Errorf("manifest differs. (-got +want):\n%s", diff)
+	}
+}
+
+func TestWithoutPlaform(t *testing.T) {
+	plb, _ := NewPlatformBuilder()
+
+	plb = plb.
+		WithOS(OS("windows")).
+		WithOS(OS("plan9")).
+		WithoutPlatform(Platform{OS("windows"), Arch("386")})
+
+	pl := plb.Build()
+	expected := []Platform{
+		{OS("windows"), Arch("amd64")},
+		{OS("plan9"), Arch("386")},
+		{OS("plan9"), Arch("amd64")},
+	}
+
+	if diff := cmp.Diff(expected, pl, cmpopts.SortSlices(lessPlatforms)); diff != "" {
+		t.Errorf("manifest differs. (-got +want):\n%s", diff)
+	}
+}
+
+func TestWithDefaults(t *testing.T) {
+	plb, _ := NewPlatformBuilder()
+
+	plb = plb.WithDefaults()
+
+	pl := plb.Build()
+
+	if len(pl) == 0 {
+		t.Errorf("expected more defaults!")
+	}
+}
+
+func lessPlatforms(x, y Platform) bool {
+	if x.OS < y.OS {
+		return true
+	}
+	if x.OS > y.OS {
+		return false
+	}
+	return x.Arch < y.Arch
+}