diff --git a/cmd/main_test.go b/cmd/main_test.go
new file mode 100644
index 0000000..124b54c
--- /dev/null
+++ b/cmd/main_test.go
@@ -0,0 +1,255 @@
+package main
+
+import (
+	"os"
+	"reflect"
+	"testing"
+)
+
+func TestDetermineCommand(t *testing.T) {
+	tests := []struct {
+		name        string
+		programName string
+		args        []string
+		wantCmd     string
+		wantArgs    []string
+	}{
+		{
+			name:        "git-get with no args",
+			programName: "git-get",
+			args:        []string{"git-get"},
+			wantCmd:     "get",
+			wantArgs:    []string{},
+		},
+		{
+			name:        "git-get with repo arg",
+			programName: "git-get",
+			args:        []string{"git-get", "user/repo"},
+			wantCmd:     "get",
+			wantArgs:    []string{"user/repo"},
+		},
+		{
+			name:        "git-get with get subcommand",
+			programName: "git-get",
+			args:        []string{"git-get", "get", "user/repo"},
+			wantCmd:     "get",
+			wantArgs:    []string{"user/repo"},
+		},
+		{
+			name:        "git-get with list subcommand",
+			programName: "git-get",
+			args:        []string{"git-get", "list"},
+			wantCmd:     "list",
+			wantArgs:    []string{},
+		},
+		{
+			name:        "git-list with no args",
+			programName: "git-list",
+			args:        []string{"git-list"},
+			wantCmd:     "list",
+			wantArgs:    []string{},
+		},
+		{
+			name:        "git-list with args",
+			programName: "git-list",
+			args:        []string{"git-list", "--fetch"},
+			wantCmd:     "list",
+			wantArgs:    []string{"--fetch"},
+		},
+		{
+			name:        "git-get.exe on Windows",
+			programName: "git-get.exe",
+			args:        []string{"git-get.exe", "user/repo"},
+			wantCmd:     "get",
+			wantArgs:    []string{"user/repo"},
+		},
+		{
+			name:        "unknown program name with args",
+			programName: "some-other-name",
+			args:        []string{"some-other-name", "get", "user/repo"},
+			wantCmd:     "get",
+			wantArgs:    []string{"user/repo"},
+		},
+		{
+			name:        "unknown program name with no args",
+			programName: "some-other-name",
+			args:        []string{"some-other-name"},
+			wantCmd:     "get",
+			wantArgs:    []string{},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Save original os.Args
+			oldArgs := os.Args
+			defer func() { os.Args = oldArgs }()
+
+			// Set test args
+			os.Args = tt.args
+
+			gotCmd, gotArgs := determineCommand()
+
+			if gotCmd != tt.wantCmd {
+				t.Errorf("determineCommand() command = %v, want %v", gotCmd, tt.wantCmd)
+			}
+
+			if !reflect.DeepEqual(gotArgs, tt.wantArgs) {
+				t.Errorf("determineCommand() args = %v, want %v", gotArgs, tt.wantArgs)
+			}
+		})
+	}
+}
+
+func TestHandleGitGetInvocation(t *testing.T) {
+	tests := []struct {
+		name     string
+		args     []string
+		wantCmd  string
+		wantArgs []string
+	}{
+		{
+			name:     "no args",
+			args:     []string{"git-get"},
+			wantCmd:  "get",
+			wantArgs: []string{},
+		},
+		{
+			name:     "with repo arg",
+			args:     []string{"git-get", "user/repo"},
+			wantCmd:  "get",
+			wantArgs: []string{"user/repo"},
+		},
+		{
+			name:     "with get subcommand",
+			args:     []string{"git-get", "get", "user/repo"},
+			wantCmd:  "get",
+			wantArgs: []string{"user/repo"},
+		},
+		{
+			name:     "with list subcommand",
+			args:     []string{"git-get", "list", "--fetch"},
+			wantCmd:  "list",
+			wantArgs: []string{"--fetch"},
+		},
+		{
+			name:     "with invalid subcommand",
+			args:     []string{"git-get", "invalid", "user/repo"},
+			wantCmd:  "get",
+			wantArgs: []string{"invalid", "user/repo"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Save original os.Args
+			oldArgs := os.Args
+			defer func() { os.Args = oldArgs }()
+
+			// Set test args
+			os.Args = tt.args
+
+			gotCmd, gotArgs := handleGitGetInvocation()
+
+			if gotCmd != tt.wantCmd {
+				t.Errorf("handleGitGetInvocation() command = %v, want %v", gotCmd, tt.wantCmd)
+			}
+
+			if !reflect.DeepEqual(gotArgs, tt.wantArgs) {
+				t.Errorf("handleGitGetInvocation() args = %v, want %v", gotArgs, tt.wantArgs)
+			}
+		})
+	}
+}
+
+func TestHandleGitListInvocation(t *testing.T) {
+	tests := []struct {
+		name     string
+		args     []string
+		wantCmd  string
+		wantArgs []string
+	}{
+		{
+			name:     "no args",
+			args:     []string{"git-list"},
+			wantCmd:  "list",
+			wantArgs: []string{},
+		},
+		{
+			name:     "with flags",
+			args:     []string{"git-list", "--fetch", "--out", "flat"},
+			wantCmd:  "list",
+			wantArgs: []string{"--fetch", "--out", "flat"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Save original os.Args
+			oldArgs := os.Args
+			defer func() { os.Args = oldArgs }()
+
+			// Set test args
+			os.Args = tt.args
+
+			gotCmd, gotArgs := handleGitListInvocation()
+
+			if gotCmd != tt.wantCmd {
+				t.Errorf("handleGitListInvocation() command = %v, want %v", gotCmd, tt.wantCmd)
+			}
+
+			if !reflect.DeepEqual(gotArgs, tt.wantArgs) {
+				t.Errorf("handleGitListInvocation() args = %v, want %v", gotArgs, tt.wantArgs)
+			}
+		})
+	}
+}
+
+func TestHandleDefaultInvocation(t *testing.T) {
+	tests := []struct {
+		name     string
+		args     []string
+		wantCmd  string
+		wantArgs []string
+	}{
+		{
+			name:     "no args",
+			args:     []string{"some-program"},
+			wantCmd:  "get",
+			wantArgs: []string{},
+		},
+		{
+			name:     "with command arg",
+			args:     []string{"some-program", "list"},
+			wantCmd:  "list",
+			wantArgs: []string{},
+		},
+		{
+			name:     "with command and args",
+			args:     []string{"some-program", "get", "user/repo", "--branch", "main"},
+			wantCmd:  "get",
+			wantArgs: []string{"user/repo", "--branch", "main"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Save original os.Args
+			oldArgs := os.Args
+			defer func() { os.Args = oldArgs }()
+
+			// Set test args
+			os.Args = tt.args
+
+			gotCmd, gotArgs := handleDefaultInvocation()
+
+			if gotCmd != tt.wantCmd {
+				t.Errorf("handleDefaultInvocation() command = %v, want %v", gotCmd, tt.wantCmd)
+			}
+
+			if !reflect.DeepEqual(gotArgs, tt.wantArgs) {
+				t.Errorf("handleDefaultInvocation() args = %v, want %v", gotArgs, tt.wantArgs)
+			}
+		})
+	}
+}
\ No newline at end of file