git_test.go

package main

import (
	"testing"
	"time"
)

func TestParseCommits(t *testing.T) {
	input := `a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2|Alice|alice@example.com|2024-12-15T10:30:00+09:00|Add feature X

 3 files changed, 45 insertions(+), 12 deletions(-)
b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3|Bob|bob@example.com|2024-12-14T14:00:00+09:00|Fix bug Y

 1 file changed, 5 insertions(+), 2 deletions(-)
c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4|Alice|alice@example.com|2024-12-13T09:15:00+09:00|Refactor Z

 7 files changed, 120 insertions(+), 80 deletions(-)
`

	commits, err := parseCommits(input)
	if err != nil {
		t.Fatalf("parseCommits failed: %v", err)
	}

	if len(commits) != 3 {
		t.Fatalf("expected 3 commits, got %d", len(commits))
	}

	// Check first commit
	c := commits[0]
	if c.Author != "Alice" {
		t.Errorf("expected author Alice, got %s", c.Author)
	}
	if c.Email != "alice@example.com" {
		t.Errorf("expected email alice@example.com, got %s", c.Email)
	}
	if c.Message != "Add feature X" {
		t.Errorf("expected message 'Add feature X', got '%s'", c.Message)
	}
	if c.FilesChanged != 3 {
		t.Errorf("expected 3 files changed, got %d", c.FilesChanged)
	}
	if c.Insertions != 45 {
		t.Errorf("expected 45 insertions, got %d", c.Insertions)
	}
	if c.Deletions != 12 {
		t.Errorf("expected 12 deletions, got %d", c.Deletions)
	}

	// Check second commit
	c2 := commits[1]
	if c2.Author != "Bob" {
		t.Errorf("expected author Bob, got %s", c2.Author)
	}
	if c2.FilesChanged != 1 {
		t.Errorf("expected 1 file changed, got %d", c2.FilesChanged)
	}
}

func TestParseCommitsEmpty(t *testing.T) {
	commits, err := parseCommits("")
	if err != nil {
		t.Fatalf("parseCommits failed: %v", err)
	}
	if len(commits) != 0 {
		t.Fatalf("expected 0 commits, got %d", len(commits))
	}
}

func TestParseStatLine(t *testing.T) {
	tests := []struct {
		line     string
		files    int
		ins      int
		del      int
	}{
		{"3 files changed, 45 insertions(+), 12 deletions(-)", 3, 45, 12},
		{"1 file changed, 5 insertions(+)", 1, 5, 0},
		{"1 file changed, 2 deletions(-)", 1, 0, 2},
		{"10 files changed, 100 insertions(+), 50 deletions(-)", 10, 100, 50},
	}

	for _, tt := range tests {
		c := &Commit{}
		parseStatLine(tt.line, c)
		if c.FilesChanged != tt.files {
			t.Errorf("line %q: expected %d files, got %d", tt.line, tt.files, c.FilesChanged)
		}
		if c.Insertions != tt.ins {
			t.Errorf("line %q: expected %d insertions, got %d", tt.line, tt.ins, c.Insertions)
		}
		if c.Deletions != tt.del {
			t.Errorf("line %q: expected %d deletions, got %d", tt.line, tt.del, c.Deletions)
		}
	}
}

func TestParseFileChurn(t *testing.T) {
	input := `a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2|Alice
10	5	src/main.go
3	1	src/util.go
b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3|Bob
8	2	src/main.go
`

	files, err := parseFileChurn(input)
	if err != nil {
		t.Fatalf("parseFileChurn failed: %v", err)
	}

	if len(files) != 2 {
		t.Fatalf("expected 2 files, got %d", len(files))
	}

	// main.go should be first (most changes)
	if files[0].Path != "src/main.go" {
		t.Errorf("expected src/main.go first, got %s", files[0].Path)
	}
	if files[0].Changes != 2 {
		t.Errorf("expected 2 changes for main.go, got %d", files[0].Changes)
	}
	if files[0].Insertions != 18 {
		t.Errorf("expected 18 insertions for main.go, got %d", files[0].Insertions)
	}
	if files[0].Deletions != 7 {
		t.Errorf("expected 7 deletions for main.go, got %d", files[0].Deletions)
	}

	// Check authors
	if files[0].Authors["Alice"] != 1 {
		t.Errorf("expected Alice to have 1 change, got %d", files[0].Authors["Alice"])
	}
	if files[0].Authors["Bob"] != 1 {
		t.Errorf("expected Bob to have 1 change, got %d", files[0].Authors["Bob"])
	}
}

func TestSortFileChurn(t *testing.T) {
	files := []FileChurn{
		{Path: "a.go", Changes: 3},
		{Path: "b.go", Changes: 10},
		{Path: "c.go", Changes: 1},
		{Path: "d.go", Changes: 7},
	}

	sortFileChurn(files)

	if files[0].Path != "b.go" || files[0].Changes != 10 {
		t.Errorf("expected b.go(10) first, got %s(%d)", files[0].Path, files[0].Changes)
	}
	if files[1].Path != "d.go" || files[1].Changes != 7 {
		t.Errorf("expected d.go(7) second, got %s(%d)", files[1].Path, files[1].Changes)
	}
	if files[3].Path != "c.go" || files[3].Changes != 1 {
		t.Errorf("expected c.go(1) last, got %s(%d)", files[3].Path, files[3].Changes)
	}
}

func TestFilterByAuthor(t *testing.T) {
	commits := []Commit{
		{Author: "Alice Smith"},
		{Author: "Bob Jones"},
		{Author: "Alice Johnson"},
		{Author: "Charlie"},
	}

	filtered := FilterByAuthor(commits, "alice")
	if len(filtered) != 2 {
		t.Errorf("expected 2 commits for 'alice', got %d", len(filtered))
	}

	filtered = FilterByAuthor(commits, "CHARLIE")
	if len(filtered) != 1 {
		t.Errorf("expected 1 commit for 'CHARLIE', got %d", len(filtered))
	}

	filtered = FilterByAuthor(commits, "nobody")
	if len(filtered) != 0 {
		t.Errorf("expected 0 commits for 'nobody', got %d", len(filtered))
	}
}

func makeTime(year, month, day, hour int) time.Time {
	return time.Date(year, time.Month(month), day, hour, 0, 0, 0, time.UTC)
}