report: do not return an error if report file does not exist

When scan running, it will try to load the previous report file to
minimize re-scanning of file that has been applied or detected (regular
or binary).
If the report file does not exist, do not return the error, keep going.

6 files changed, 111 insertions, 53 deletions

diff --git a/file.go b/file.go
index 80780d1..80c369c 100644
--- a/file.go
+++ b/file.go
@@ -119,7 +119,7 @@ func (f *file) initLines(content []byte, maxLine int) (err error) {
 		f.lines = f.lines[maxLine : nline-maxLine]
 	}
 
-	if bytes.HasPrefix(f.topLines[0], []byte(`#!`)) {
+	if len(f.topLines) != 0 && bytes.HasPrefix(f.topLines[0], []byte(`#!`)) {
 		f.hasSheBang = true
 	}
 	return nil
diff --git a/report.go b/report.go
index 6a38f8d..ae298f4 100644
--- a/report.go
+++ b/report.go
@@ -52,9 +52,14 @@ func newReport() (rep *report) {
 // loadReport load the [ReportFile] from the current directory.
 func loadReport() (rep *report, err error) {
 	var logp = `loadReport`
+
+	rep = newReport()
 	var content []byte
 	content, err = os.ReadFile(ReportFile)
 	if err != nil {
+		if os.IsNotExist(err) {
+			return rep, nil
+		}
 		return nil, fmt.Errorf(`%s: %w`, logp, err)
 	}
 
@@ -64,7 +69,6 @@ func loadReport() (rep *report, err error) {
 	csvr.ReuseRecord = true
 	csvr.TrimLeadingSpace = true
 
-	rep = newReport()
 	var group string
 	var record []string
 	var f *file
diff --git a/spdxconv_test.go b/spdxconv_test.go
index 84b3718..d2389e4 100644
--- a/spdxconv_test.go
+++ b/spdxconv_test.go
@@ -8,7 +8,6 @@ import (
 	"regexp"
 	"testing"
 
-	"git.sr.ht/~shulhan/pakakeh.go/lib/git"
 	"git.sr.ht/~shulhan/pakakeh.go/lib/test"
 )
 
@@ -121,54 +120,46 @@ func TestInit(t *testing.T) {
 }
 
 func TestScan(t *testing.T) {
-	const scanDir = `testdata/scan/`
-	t.Chdir(scanDir)
+	// Populate the test files into `testdata/`.
 
-	err := Scan(`.`)
+	var testData *test.Data
+	var err error
+	testData, err = test.LoadData(`testdata/Scan_test.txt`)
 	if err != nil {
 		t.Fatal(err)
 	}
+	var tempDir = `testdata/`
+	testData.ExtractInput(tempDir)
 
-	got, err := os.ReadFile(ReportFile)
-	if err != nil {
-		t.Fatal(err)
-	}
+	// Run the test ...
 
-	exp := `// SPDX-License-Identifier: CC0-1.0
-// SPDX-FileCopyrightText: 2026 M. Shulhan <ms@kilabit.info>
+	listCase := []struct {
+		dir       string
+		expReport string
+	}{{
+		dir:       `testdata/scan/`,
+		expReport: string(testData.Output[`scan/spdxconv.report`]),
+	}, {
+		dir:       `testdata/Scan_noConfigAndReport/`,
+		expReport: string(testData.Output[`Scan_noConfigAndReport/spdxconv.report`]),
+	}}
+	for _, tc := range listCase {
+		t.Run(tc.dir, func(tt *testing.T) {
+			tt.Chdir(tc.dir)
 
-//spdxconv:version:v1
-//spdxconv:header:path,license_id,idx_license_id,year,copyright_id,idx_copyright_id
-//
-//spdxconv:regular
-//
-Makefile,default,0,2025,default,0,#,
-go.mod,default,0,2025,default,0,//,
-no_copyright_year.md,match,2,2026,default,0,<!--,-->
-po/included.go,match,1,2026,match,0,//,
-test.go,match,1,2022,match,0,//,
-test.html,match,4,2022,match,1,<!--,-->
-test.sh,default,0,2026,default,0,#,
-test.sql,match,1,2022,match,0,--,
-//
-//spdxconv:binary
-//
-go.sum,default,0,2025,default,0,,
-test.json,default,0,2026,default,0,,
-//
-//spdxconv:unknown
-//
-//
-//spdxconv:done
-//
-.gitignore,exist,0,,exist,1,#,
-a/b/.gitignore,exist,0,,exist,1,#,
-po/test.po,,0,,,0,,
-po/test.pot,,0,,,0,,
-with_spdx.go,exist,0,,exist,1,//,
-`
+			err := Scan(`.`)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			got, err := os.ReadFile(ReportFile)
+			if err != nil {
+				t.Fatal(err)
+			}
 
-	test.Assert(t, `Scan: `+scanDir, exp, string(got))
+			test.Assert(t, `Scan: `+tc.dir, tc.expReport, string(got))
+		})
+	}
 }
 
 func TestApply(t *testing.T) {
@@ -259,19 +250,12 @@ func TestNew(t *testing.T) {
 	testData.ExtractInput(tempDir)
 	t.Chdir(tempDir)
 
-	var gitRoot *git.Git
-	gitRoot, err = git.New(`.`)
-	if err != nil {
-		t.Fatal(err)
-	}
-
 	var listCase = []testCase{{
 		dir: `.`,
 		exp: &SPDXConv{
 			curDir: tempDir,
 			dir:    tempDir,
-			scmDir: tempDir,
-			scm:    gitRoot,
+			scm:    defaultNoSCM,
 		},
 	}, {
 		dir:      `/tmp`,
diff --git a/testdata/Scan_noConfigAndReport/.gitignore b/testdata/Scan_noConfigAndReport/.gitignore
new file mode 100644
index 0000000..405fc5e
--- /dev/null
+++ b/testdata/Scan_noConfigAndReport/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+# SPDX-FileCopyrightText: 2026 M. Shulhan <ms@kilabit.info>
+
+*
+!/.gitignore
diff --git a/testdata/Scan_test.txt b/testdata/Scan_test.txt
new file mode 100644
index 0000000..dca80da
--- /dev/null
+++ b/testdata/Scan_test.txt
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: CC0-1.0
+// SPDX-FileCopyrightText: 2026 M. Shulhan <ms@kilabit.info>
+
+Test spdxconv.Scan function.
+
+>>> scan/spdxconv.report
+// Reset the report.
+
+<<< scan/spdxconv.report
+// SPDX-License-Identifier: CC0-1.0
+// SPDX-FileCopyrightText: 2026 M. Shulhan <ms@kilabit.info>
+
+//spdxconv:version:v1
+//spdxconv:header:path,license_id,idx_license_id,year,copyright_id,idx_copyright_id
+//
+//spdxconv:regular
+//
+Makefile,default,0,2026,default,0,#,
+go.mod,default,0,2026,default,0,//,
+no_copyright_year.md,match,2,2026,default,0,<!--,-->
+po/included.go,match,1,2026,match,0,//,
+test.go,match,1,2022,match,0,//,
+test.html,match,4,2022,match,1,<!--,-->
+test.sh,default,0,2026,default,0,#,
+test.sql,match,1,2022,match,0,--,
+//
+//spdxconv:binary
+//
+go.sum,default,0,2026,default,0,,
+test.json,default,0,2026,default,0,,
+//
+//spdxconv:unknown
+//
+//
+//spdxconv:done
+//
+.gitignore,exist,0,,exist,1,#,
+a/b/.gitignore,exist,0,,exist,1,#,
+po/test.po,,0,,,0,,
+po/test.pot,,0,,,0,,
+with_spdx.go,exist,0,,exist,1,//,
+
+>>> Scan_noConfigAndReport/spdxconv.report
+// Reset the report.
+
+<<< Scan_noConfigAndReport/spdxconv.report
+// SPDX-License-Identifier: CC0-1.0
+// SPDX-FileCopyrightText: 2026 M. Shulhan <ms@kilabit.info>
+
+//spdxconv:version:v1
+//spdxconv:header:path,license_id,idx_license_id,year,copyright_id,idx_copyright_id
+//
+//spdxconv:regular
+//
+//
+//spdxconv:binary
+//
+//
+//spdxconv:unknown
+//
+.gitignore,,0,,,0,,
+//
+//spdxconv:done
+//
diff --git a/testdata/scan/.gitignore b/testdata/scan/.gitignore
index c13f6d6..d7514af 100644
--- a/testdata/scan/.gitignore
+++ b/testdata/scan/.gitignore
@@ -1,7 +1,8 @@
 # SPDX-License-Identifier: GPL-3.0-only
 # SPDX-FileCopyrightText: 2025 M. Shulhan <ms@kilabit.info>
 
-node_modules/
-*.html
 !test.html
+*.html
+node_modules/
+spdxconv.report
 vendor/