dashboard/app: test coverage /file link

1. Init coveragedb client once and propagate it through context to enable mocking.
2. Always init coverage handlers. It simplifies testing.
3. Read webGit and coveragedb client from ctx to make it mockable.
4. Use int for file line number and int64 for merged coverage.
5. Add tests.

1 files changed, 171 insertions, 0 deletions

diff --git a/dashboard/app/coverage_test.go b/dashboard/app/coverage_test.go
new file mode 100644
index 000000000..ef8321c9f
--- /dev/null
+++ b/dashboard/app/coverage_test.go
@@ -0,0 +1,171 @@
+// Copyright 2025 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/google/syzkaller/pkg/coveragedb"
+	"github.com/google/syzkaller/pkg/coveragedb/mocks"
+	"github.com/google/syzkaller/pkg/coveragedb/spannerclient"
+	"github.com/google/syzkaller/pkg/covermerger"
+	mergermocks "github.com/google/syzkaller/pkg/covermerger/mocks"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+	"google.golang.org/api/iterator"
+)
+
+func TestFileCoverage(t *testing.T) {
+	tests := []struct {
+		name      string
+		covDB     func(t *testing.T) spannerclient.SpannerClient
+		fileProv  func(t *testing.T) covermerger.FileVersProvider
+		url       string
+		wantInRes []string
+	}{
+		{
+			name:     "empty db",
+			covDB:    func(t *testing.T) spannerclient.SpannerClient { return emptyCoverageDBFixture(t, 1) },
+			fileProv: func(t *testing.T) covermerger.FileVersProvider { return staticFileProvider(t) },
+			url: "/test2/graph/coverage/file?dateto=2025-01-31&period=month" +
+				"&commit=c0e75905caf368e19aab585d20151500e750de89&filepath=virt/kvm/kvm_main.c",
+			wantInRes: []string{"1 line1"},
+		},
+		{
+			name:     "regular db",
+			covDB:    func(t *testing.T) spannerclient.SpannerClient { return coverageDBFixture(t) },
+			fileProv: func(t *testing.T) covermerger.FileVersProvider { return staticFileProvider(t) },
+			url: "/test2/graph/coverage/file?dateto=2025-01-31&period=month" +
+				"&commit=c0e75905caf368e19aab585d20151500e750de89&filepath=virt/kvm/kvm_main.c",
+			wantInRes: []string{
+				"4      1 line1",
+				"5      2 line2",
+				"6      3 line3"},
+		},
+		{
+			name:     "multimanager db",
+			covDB:    func(t *testing.T) spannerclient.SpannerClient { return multiManagerCovDBFixture(t) },
+			fileProv: func(t *testing.T) covermerger.FileVersProvider { return staticFileProvider(t) },
+			url: "/test2/graph/coverage/file?dateto=2025-01-31&period=month" +
+				"&commit=c0e75905caf368e19aab585d20151500e750de89&filepath=virt/kvm/kvm_main.c" +
+				"&manager=special-cc-manager&unique-only=1",
+			wantInRes: []string{
+				" 0      1 line1", // Covered, is not unique.
+				" 5      2 line2", // Covered and is unique.
+				"        3 line3", // Covered only by "*" managers.
+			},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			c := NewCtx(t)
+			defer c.Close()
+			c.setCoverageMocks("test2", test.covDB(t), test.fileProv(t))
+			fileCovPage, err := c.GET(test.url)
+			assert.NoError(t, err)
+			got := string(fileCovPage)
+			for _, want := range test.wantInRes {
+				if !strings.Contains(got, want) {
+					t.Errorf(`"%s" wasn't found in "%s"'`, want, got)
+				}
+			}
+		})
+	}
+}
+
+func staticFileProvider(t *testing.T) covermerger.FileVersProvider {
+	m := mergermocks.NewFileVersProvider(t)
+	m.On("GetFileVersions", mock.Anything, mock.Anything).
+		Return(func(targetFilePath string, repoCommits ...covermerger.RepoCommit,
+		) covermerger.FileVersions {
+			res := covermerger.FileVersions{}
+			for _, rc := range repoCommits {
+				res[rc] = `line1
+line2
+line3`
+			}
+			return res
+		}, nil)
+	return m
+}
+
+func emptyCoverageDBFixture(t *testing.T, times int) spannerclient.SpannerClient {
+	mRowIterator := mocks.NewRowIterator(t)
+	mRowIterator.On("Stop").Return().Times(times)
+	mRowIterator.On("Next").
+		Return(nil, iterator.Done).Times(times)
+
+	mTran := mocks.NewReadOnlyTransaction(t)
+	mTran.On("Query", mock.Anything, mock.Anything).
+		Return(mRowIterator).Times(times)
+
+	m := mocks.NewSpannerClient(t)
+	m.On("Single").
+		Return(mTran).Times(times)
+	return m
+}
+
+func coverageDBFixture(t *testing.T) spannerclient.SpannerClient {
+	mRowIt := newRowIteratorMock(t, []*coveragedb.LinesCoverage{{
+		LinesInstrumented: []int64{1, 2, 3},
+		HitCounts:         []int64{4, 5, 6},
+	}})
+
+	mTran := mocks.NewReadOnlyTransaction(t)
+	mTran.On("Query", mock.Anything, mock.Anything).
+		Return(mRowIt).Once()
+
+	m := mocks.NewSpannerClient(t)
+	m.On("Single").
+		Return(mTran).Once()
+	return m
+}
+
+func multiManagerCovDBFixture(t *testing.T) spannerclient.SpannerClient {
+	mReadFullCoverageTran := mocks.NewReadOnlyTransaction(t)
+	mReadFullCoverageTran.On("Query", mock.Anything, mock.Anything).
+		Return(newRowIteratorMock(t, []*coveragedb.LinesCoverage{{
+			LinesInstrumented: []int64{1, 2, 3},
+			HitCounts:         []int64{4, 5, 6},
+		}})).Once()
+
+	mReadPartialCoverageTran := mocks.NewReadOnlyTransaction(t)
+	mReadPartialCoverageTran.On("Query", mock.Anything, mock.Anything).
+		Return(newRowIteratorMock(t, []*coveragedb.LinesCoverage{{
+			LinesInstrumented: []int64{1, 2},
+			HitCounts:         []int64{3, 5},
+		}})).Once()
+
+	m := mocks.NewSpannerClient(t)
+	// The order matters. Full coverage is fetched second.
+	m.On("Single").
+		Return(mReadPartialCoverageTran).Once()
+	m.On("Single").
+		Return(mReadFullCoverageTran).Once()
+
+	return m
+}
+
+func newRowIteratorMock(t *testing.T, cov []*coveragedb.LinesCoverage,
+) *mocks.RowIterator {
+	m := mocks.NewRowIterator(t)
+	m.On("Stop").Once().Return()
+	for _, item := range cov {
+		mRow := mocks.NewRow(t)
+		mRow.On("ToStruct", mock.Anything).
+			Run(func(args mock.Arguments) {
+				arg := args.Get(0).(*coveragedb.LinesCoverage)
+				*arg = *item
+			}).
+			Return(nil).Once()
+
+		m.On("Next").
+			Return(mRow, nil).Once()
+	}
+
+	m.On("Next").
+		Return(nil, iterator.Done).Once()
+	return m
+}