Add test.c for RULE-7-4

Author: jeongsoolee09

c/misra/test/rules/RULE-7-4/test.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+
+void sample1() {
+  const char *s1 =
+      "string"; // COMPLIANT: string literal assigned to a const char* variable
+  const register volatile char *s2 =
+      "string"; // COMPLIANT: string literal assigned to a const char* variable,
+                // don't care about the qualifiers
+  char *s3 =
+      "string"; // NON_COMPLIANT: string literal assigned to a char* variable
+  s2 = s3;      // COMPLIANT: string literal assigned to a char* variable
+  s3 = s2;      // NON_COMPLIANT: string literal assigned to a char* variable
+}
+
+const char *sample2(int x) {
+  if (x == 1)
+    return "string"; // COMPLIANT: can return a string literal with return type
+                     // being const char* being const char*
+  else
+    return NULL;
+}
+
+char *sample3(int x) {
+  if (x == 1)
+    return "string"; // NON_COMPLIANT: can return a string literal with return
+                     // type being char*
+  else
+    return NULL;
+}
+
+const char *sample6(int x) {
+  const char *result;
+  if (x == 1)
+    result = "string"; // COMPLIANT: string literal assigned to a const char*
+                       // variable
+  else
+    result = NULL;
+
+  return result; // COMPLIANT: `result` can be a string literal with return type
+                 // being const char*
+}
+
+void sample4(char *string) {}
+
+void sample5(const char *string) {}
+
+void call45() {
+  const char *literal = "string";
+  sample4(literal);  // NON_COMPLIANT: can't pass string literal to char*
+  sample4("string"); // NON_COMPLIANT: can't pass string literal to char*
+  sample5(literal);  // COMPLIANT: passing string literal to const char*
+  sample5("string"); // COMPLIANT: passing string literal to const char*
+}
+
+int main() { return 0; }