Added a Breadth-first top down walk function
to policy_walk.

Test: m droid dist
Change-Id: I678d2a2402c7c3ab446e8533c9f862cd8f54f889
diff --git a/tools/compliance/policy_walk_test.go b/tools/compliance/policy_walk_test.go
index c55e2f8..0bc37f8 100644
--- a/tools/compliance/policy_walk_test.go
+++ b/tools/compliance/policy_walk_test.go
@@ -16,9 +16,22 @@
 
 import (
 	"bytes"
+	"fmt"
+	"os"
+	"strings"
 	"testing"
 )
 
+func TestMain(m *testing.M) {
+	// Change into the cmd directory before running the tests
+	// so they can find the testdata directory.
+	if err := os.Chdir("cmd"); err != nil {
+		fmt.Printf("failed to change to testdata directory: %s\n", err)
+		os.Exit(1)
+	}
+	os.Exit(m.Run())
+}
+
 func TestWalkResolutionsForCondition(t *testing.T) {
 	tests := []struct {
 		name                string
@@ -1197,3 +1210,417 @@
 		})
 	}
 }
+
+func TestWalkTopDownBreadthFirst(t *testing.T) {
+	tests := []struct {
+		name           string
+		roots          []string
+		edges          []annotated
+		expectedResult []string
+	}{
+		{
+			name:  "bin/bin1",
+			roots: []string{"bin/bin1.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin2",
+			roots: []string{"bin/bin2.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin3",
+			roots: []string{"bin/bin3.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin3.meta_lic",
+			},
+		},
+		{
+			name:  "lib/liba.so",
+			roots: []string{"lib/liba.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/liba.so.meta_lic",
+			},
+		},
+		{
+			name:  "lib/libb.so",
+			roots: []string{"lib/libb.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/libb.so.meta_lic",
+			},
+		},
+		{
+			name:  "lib/libc.so",
+			roots: []string{"lib/libc.a.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/libc.a.meta_lic",
+			},
+		},
+		{
+			name:  "lib/libd.so",
+			roots: []string{"lib/libd.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "highest.apex",
+			roots: []string{"highest.apex.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/highest.apex.meta_lic",
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "container.zip",
+			roots: []string{"container.zip.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/container.zip.meta_lic",
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "application",
+			roots: []string{"application.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/application.meta_lic",
+				"testdata/notice/bin/bin3.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin1&lib/liba",
+			roots: []string{"bin/bin1.meta_lic","lib/liba.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin2&lib/libd",
+			roots: []string{"bin/bin2.meta_lic", "lib/libd.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "application&bin/bin3",
+			roots: []string{"application.meta_lic", "bin/bin3.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/application.meta_lic",
+				"testdata/notice/bin/bin3.meta_lic",
+				"testdata/notice/bin/bin3.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+			},
+		},
+		{
+			name:  "highest.apex&container.zip",
+			roots: []string{"highest.apex.meta_lic", "container.zip.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/highest.apex.meta_lic",
+				"testdata/notice/container.zip.meta_lic",
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			stderr := &bytes.Buffer{}
+			actualOut := &bytes.Buffer{}
+
+			rootFiles := make([]string, 0, len(tt.roots))
+			for _, r := range tt.roots {
+				rootFiles = append(rootFiles, "testdata/notice/"+r)
+			}
+
+			lg, err := ReadLicenseGraph(GetFS(""), stderr, rootFiles)
+
+			if err != nil {
+				t.Errorf("unexpected test data error: got %s, want no error", err)
+				return
+			}
+
+			expectedRst := tt.expectedResult
+
+			WalkTopDownBreadthFirst(nil, lg, func(lg *LicenseGraph, tn *TargetNode, path TargetEdgePath) bool {
+				fmt.Fprintln(actualOut, tn.Name())
+				return true
+			})
+
+			actualRst := strings.Split(actualOut.String(), "\n")
+
+			if len(actualRst) > 0 {
+				actualRst = actualRst[:len(actualRst)-1]
+			}
+
+			t.Logf("actual nodes visited: %s", actualOut.String())
+			t.Logf("expected nodes visited: %s", strings.Join(expectedRst, "\n"))
+
+			if len(actualRst) != len(expectedRst) {
+				t.Errorf("WalkTopDownBreadthFirst: number of visited nodes is different: got %d, want %d", len(actualRst), len(expectedRst))
+			}
+
+			for i := 0; i < len(actualRst) && i < len(expectedRst); i++ {
+				if actualRst[i] != expectedRst[i] {
+					t.Errorf("WalkTopDownBreadthFirst: lines differ at index %d: got %q, want %q", i, actualRst[i], expectedRst[i])
+					break
+				}
+			}
+
+			if len(actualRst) < len(expectedRst) {
+				t.Errorf("WalkTopDownBreadthFirst: extra lines at %d: got %q, want nothing", len(actualRst), expectedRst[len(actualRst)])
+			}
+
+			if len(expectedRst) < len(actualRst) {
+				t.Errorf("WalkTopDownBreadthFirst: missing lines at %d: got nothing, want %q", len(expectedRst), actualRst[len(expectedRst)])
+			}
+		})
+	}
+}
+
+func TestWalkTopDownBreadthFirstWithoutDuplicates(t *testing.T) {
+	tests := []struct {
+		name           string
+		roots          []string
+		edges          []annotated
+		expectedResult []string
+	}{
+		{
+			name:  "bin/bin1",
+			roots: []string{"bin/bin1.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin2",
+			roots: []string{"bin/bin2.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin3",
+			roots: []string{"bin/bin3.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin3.meta_lic",
+			},
+		},
+		{
+			name:  "lib/liba.so",
+			roots: []string{"lib/liba.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/liba.so.meta_lic",
+			},
+		},
+		{
+			name:  "lib/libb.so",
+			roots: []string{"lib/libb.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/libb.so.meta_lic",
+			},
+		},
+		{
+			name:  "lib/libc.so",
+			roots: []string{"lib/libc.a.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/libc.a.meta_lic",
+			},
+		},
+		{
+			name:  "lib/libd.so",
+			roots: []string{"lib/libd.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "highest.apex",
+			roots: []string{"highest.apex.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/highest.apex.meta_lic",
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "container.zip",
+			roots: []string{"container.zip.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/container.zip.meta_lic",
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+		{
+			name:  "application",
+			roots: []string{"application.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/application.meta_lic",
+				"testdata/notice/bin/bin3.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin1&lib/liba",
+			roots: []string{"bin/bin1.meta_lic", "lib/liba.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+			},
+		},
+		{
+			name:  "bin/bin2&lib/libd",
+			roots: []string{"bin/bin2.meta_lic", "lib/libd.so.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+			},
+		},
+		{
+			name:  "application&bin/bin3",
+			roots: []string{"application.meta_lic", "bin/bin3.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/application.meta_lic",
+				"testdata/notice/bin/bin3.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+			},
+		},
+		{
+			name:  "highest.apex&container.zip",
+			roots: []string{"highest.apex.meta_lic", "container.zip.meta_lic"},
+			expectedResult: []string{
+				"testdata/notice/highest.apex.meta_lic",
+				"testdata/notice/container.zip.meta_lic",
+				"testdata/notice/bin/bin1.meta_lic",
+				"testdata/notice/bin/bin2.meta_lic",
+				"testdata/notice/lib/liba.so.meta_lic",
+				"testdata/notice/lib/libb.so.meta_lic",
+				"testdata/notice/lib/libc.a.meta_lic",
+				"testdata/notice/lib/libd.so.meta_lic",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			stderr := &bytes.Buffer{}
+			actualOut := &bytes.Buffer{}
+
+			rootFiles := make([]string, 0, len(tt.roots))
+			for _, r := range tt.roots {
+				rootFiles = append(rootFiles, "testdata/notice/"+r)
+			}
+
+			lg, err := ReadLicenseGraph(GetFS(""), stderr, rootFiles)
+
+			if err != nil {
+				t.Errorf("unexpected test data error: got %s, want no error", err)
+				return
+			}
+
+			expectedRst := tt.expectedResult
+
+			//Keeping track of the visited nodes
+			//Only add to actualOut if not visited
+			visitedNodes := make(map[string]struct{})
+			WalkTopDownBreadthFirst(nil, lg, func(lg *LicenseGraph, tn *TargetNode, path TargetEdgePath) bool {
+				if _, alreadyVisited := visitedNodes[tn.Name()]; alreadyVisited {
+					return false
+				}
+				fmt.Fprintln(actualOut, tn.Name())
+				visitedNodes[tn.Name()] = struct{}{}
+				return true
+			})
+
+			actualRst := strings.Split(actualOut.String(), "\n")
+
+			if len(actualRst) > 0 {
+				actualRst = actualRst[:len(actualRst)-1]
+			}
+
+			t.Logf("actual nodes visited: %s", actualOut.String())
+			t.Logf("expected nodes visited: %s", strings.Join(expectedRst, "\n"))
+
+			if len(actualRst) != len(expectedRst) {
+				t.Errorf("WalkTopDownBreadthFirst: number of visited nodes is different: got %d, want %d", len(actualRst), len(expectedRst))
+			}
+
+			for i := 0; i < len(actualRst) && i < len(expectedRst); i++ {
+				if actualRst[i] != expectedRst[i] {
+					t.Errorf("WalkTopDownBreadthFirst: lines differ at index %d: got %q, want %q", i, actualRst[i], expectedRst[i])
+					break
+				}
+			}
+
+			if len(actualRst) < len(expectedRst) {
+				t.Errorf("WalkTopDownBreadthFirst: extra lines at %d: got %q, want nothing", len(actualRst), expectedRst[len(actualRst)])
+			}
+
+			if len(expectedRst) < len(actualRst) {
+				t.Errorf("WalkTopDownBreadthFirst: missing lines at %d: got nothing, want %q", len(expectedRst), actualRst[len(expectedRst)])
+			}
+		})
+	}
+}