sql_composer/
mock.rs

1//! Mock table system for generating test data as `SELECT ... UNION ALL SELECT ...`.
2//!
3//! When the composer encounters a table name that has a mock registered,
4//! it can substitute a generated SELECT statement that produces the mock data.
5
6use std::collections::BTreeMap;
7
8/// A mock table definition with column data for test substitution.
9///
10/// Mock tables generate SQL of the form:
11/// ```sql
12/// SELECT 'val1' AS col1, 'val2' AS col2
13/// UNION ALL
14/// SELECT 'val3', 'val4'
15/// ```
16#[derive(Debug, Clone, PartialEq)]
17pub struct MockTable {
18    /// The name of the table being mocked.
19    pub name: String,
20    /// Rows of column name → value mappings.
21    pub rows: Vec<BTreeMap<String, String>>,
22}
23
24impl MockTable {
25    /// Create a new mock table with the given name.
26    pub fn new(name: impl Into<String>) -> Self {
27        Self {
28            name: name.into(),
29            rows: Vec::new(),
30        }
31    }
32
33    /// Add a row to this mock table.
34    pub fn add_row(&mut self, row: BTreeMap<String, String>) {
35        self.rows.push(row);
36    }
37
38    /// Generate the mock SQL for this table.
39    ///
40    /// The first row includes `AS column_name` aliases, subsequent rows omit them.
41    /// Values are quoted as SQL string literals. Use `NULL` (without quotes) for null.
42    pub fn to_sql(&self) -> String {
43        if self.rows.is_empty() {
44            return format!("SELECT NULL WHERE 1=0 /* empty mock: {} */", self.name);
45        }
46
47        // Use the first row's keys to determine column order
48        let columns: Vec<&String> = self.rows[0].keys().collect();
49
50        let mut parts = Vec::new();
51
52        for (i, row) in self.rows.iter().enumerate() {
53            let values: Vec<String> = columns
54                .iter()
55                .map(|col| {
56                    let val = row.get(*col).map(|s| s.as_str()).unwrap_or("NULL");
57                    if val == "NULL" {
58                        if i == 0 {
59                            format!("NULL AS {col}")
60                        } else {
61                            "NULL".to_string()
62                        }
63                    } else if i == 0 {
64                        format!("'{}' AS {col}", val.replace('\'', "''"))
65                    } else {
66                        format!("'{}'", val.replace('\'', "''"))
67                    }
68                })
69                .collect();
70            parts.push(format!("SELECT {}", values.join(", ")));
71        }
72
73        parts.join("\nUNION ALL\n")
74    }
75}
76
77/// Convenience macro for building mock table rows.
78///
79/// # Example
80/// ```
81/// use sql_composer::mock_rows;
82/// let rows = mock_rows![
83///     {"id" => "1", "name" => "Alice"},
84///     {"id" => "2", "name" => "Bob"},
85/// ];
86/// ```
87#[macro_export]
88macro_rules! mock_rows {
89    [$(  {$($key:literal => $val:literal),* $(,)?}  ),* $(,)?] => {
90        vec![
91            $(
92                {
93                    let mut row = ::std::collections::BTreeMap::new();
94                    $( row.insert($key.to_string(), $val.to_string()); )*
95                    row
96                }
97            ),*
98        ]
99    };
100}
101
102#[cfg(test)]
103mod tests {
104    use super::*;
105
106    #[test]
107    fn test_mock_table_single_row() {
108        let mut mock = MockTable::new("users");
109        let mut row = BTreeMap::new();
110        row.insert("id".to_string(), "1".to_string());
111        row.insert("name".to_string(), "Alice".to_string());
112        mock.add_row(row);
113
114        let sql = mock.to_sql();
115        assert_eq!(sql, "SELECT '1' AS id, 'Alice' AS name");
116    }
117
118    #[test]
119    fn test_mock_table_multiple_rows() {
120        let mut mock = MockTable::new("users");
121
122        let mut row1 = BTreeMap::new();
123        row1.insert("id".to_string(), "1".to_string());
124        row1.insert("name".to_string(), "Alice".to_string());
125        mock.add_row(row1);
126
127        let mut row2 = BTreeMap::new();
128        row2.insert("id".to_string(), "2".to_string());
129        row2.insert("name".to_string(), "Bob".to_string());
130        mock.add_row(row2);
131
132        let sql = mock.to_sql();
133        assert_eq!(
134            sql,
135            "SELECT '1' AS id, 'Alice' AS name\nUNION ALL\nSELECT '2', 'Bob'"
136        );
137    }
138
139    #[test]
140    fn test_mock_table_with_null() {
141        let mut mock = MockTable::new("users");
142        let mut row = BTreeMap::new();
143        row.insert("id".to_string(), "1".to_string());
144        row.insert("email".to_string(), "NULL".to_string());
145        mock.add_row(row);
146
147        let sql = mock.to_sql();
148        assert!(sql.contains("NULL AS email"));
149        assert!(!sql.contains("'NULL'"));
150    }
151
152    #[test]
153    fn test_mock_table_empty() {
154        let mock = MockTable::new("users");
155        let sql = mock.to_sql();
156        assert!(sql.contains("WHERE 1=0"));
157    }
158
159    #[test]
160    fn test_mock_table_sql_injection_safe() {
161        let mut mock = MockTable::new("users");
162        let mut row = BTreeMap::new();
163        row.insert("name".to_string(), "O'Brien".to_string());
164        mock.add_row(row);
165
166        let sql = mock.to_sql();
167        assert!(sql.contains("O''Brien"));
168    }
169
170    #[test]
171    fn test_mock_rows_macro() {
172        let rows = mock_rows![
173            {"id" => "1", "name" => "Alice"},
174            {"id" => "2", "name" => "Bob"},
175        ];
176        assert_eq!(rows.len(), 2);
177        assert_eq!(rows[0].get("id").unwrap(), "1");
178        assert_eq!(rows[1].get("name").unwrap(), "Bob");
179    }
180}
sql_composer/mock.rs

sql_composer/
mock.rs
