Add gengamma unit tests

tests/testthat/test-3-families.R

@@ -431,3 +431,46 @@ test_that("Binomial simulation/residuals works with weights argument or cbind()"
   expect_equal(mean(dat$y), mean(s2), tolerance = 0.1)
   expect_equal(mean(apply(s2, 1, mean) - dat$y), 0, tolerance = 0.01)
 })
+
+test_that("Generalized gamma works", {
+  d <- subset(pcod_2011, density > 0)
+  fit1 <- sdmTMB(
+    density ~ 1 + depth_scaled,
+    data = d,
+    spatial = "off",
+    family = lognormal(link = "log")
+  )
+  fit2 <- sdmTMB(
+    density ~ 1 + depth_scaled,
+    data = d,
+    spatial = "off",
+    family = Gamma(link = "log")
+  )
+  fit3 <- sdmTMB(
+    density ~ 1 + depth_scaled,
+    data = d,
+    spatial = "off",
+    family = gengamma(link = "log")
+  )
+  expect_s3_class(fit2, "sdmTMB")
+  logLik(fit1)
+  logLik(fit2)
+  logLik(fit3)
+  get_df <- function(x) {
+    L <- logLik(x)
+    attr(L, "df")
+  }
+  df1 <- get_df(fit1)
+  df2 <- get_df(fit2)
+  df3 <- get_df(fit3)
+  expect_identical(df1, 3L)
+  expect_identical(df3, 4L)
+
+  b <- as.list(fit3$sd_report, "Estimate")
+  expect_equal(b$gengamma_Q, 0.04212623, tolerance = 0.001)
+  AIC(fit1)
+  AIC(fit2)
+  AIC(fit3)
+
+  expect_error(residuals(fit3), regexp = "supported")
+})