test-renderer-bisection-method added

tests/testthat/test-renderer-bisection-method.R

@@ -0,0 +1,179 @@
+library(testthat)
+library(animint2)
+library(XML)
+
+context("Bisection Method Animation renderer")
+
+tests_init()
+
+# ----------- DATA SETUP -----------
+
+set.seed(42)
+max_iterations <- 10
+
+# f(x) = x^3 - x - 2
+f <- function(x) x^3 - x - 2
+
+a_init <- 1.0
+b_init <- 2.0
+
+bisection_data <- data.frame()
+interval_data  <- data.frame()
+
+a <- a_init
+b <- b_init
+
+for (i in 1:max_iterations) {
+  mid      <- (a + b) / 2
+  f_mid    <- f(mid)
+  f_a      <- f(a)
+
+  bisection_data <- rbind(
+    bisection_data,
+    data.frame(
+      iteration = as.integer(i),
+      midpoint  = mid,
+      f_mid     = f_mid,
+      side      = ifelse(f_mid * f_a < 0, "left", "right")
+    )
+  )
+
+  interval_data <- rbind(
+    interval_data,
+    data.frame(
+      iteration = as.integer(i),
+      a         = a,
+      b         = b,
+      y         = 0
+    )
+  )
+
+  if (f_mid * f_a < 0) {
+    b <- mid
+  } else {
+    a <- mid
+  }
+}
+
+bisection_data$iteration <- as.integer(bisection_data$iteration)
+interval_data$iteration  <- as.integer(interval_data$iteration)
+
+# x values for the curve
+curve_df <- data.frame(
+  x = seq(0.8, 2.2, length.out = 200),
+  y = f(seq(0.8, 2.2, length.out = 200)),
+  iteration = 1L
+)
+
+# ----------- VISUALIZATION -----------
+
+#static blue curve
+viz <- list(
+  bisectionPlot = ggplot() +
+    geom_line(
+      data  = curve_df,
+      aes(x = x, y = y),
+      colour = "steelblue",
+      size   = 1
+    ) +
+    geom_vline(
+      data = interval_data,
+      aes(xintercept = a),
+      showSelected = "iteration",
+      colour    = "green",
+      linetype  = "dashed",
+      size      = 1
+    ) +
+    geom_vline(
+      data = interval_data,
+      aes(xintercept = b),
+      showSelected = "iteration",
+      colour   = "orange",
+      linetype = "dashed",
+      size     = 1
+    ) +
+    geom_point(
+      data = bisection_data,
+      aes(x = midpoint, y = f_mid, colour = side),
+      showSelected  = "iteration",
+      clickSelects  = "side",
+      size = 5
+    ) +
+    geom_hline(yintercept = 0, colour = "gray50", linetype = "dotted") +
+    labs(
+      title = "Bisection Method Animation",
+      x     = "x",
+      y     = "f(x)"
+    ) +
+    theme_animint(width = 550, height = 350) +
+    theme(
+      legend.position  = "bottom",
+      legend.direction = "horizontal"
+    ),
+
+  time  = list(variable = "iteration", ms = 1000),
+  first = list(
+    iteration = 1L,
+    side      = c("left", "right")
+  )
+)
+
+info <- animint2HTML(viz)
+
+# ----------- HELPER(fetches live DOM from chrome) -----------
+
+get_point_count <- function() {
+  page  <- getHTML()
+  nodes <- getNodeSet(
+    page,
+    '//g[starts-with(@class, "geom") and contains(@class, "point")]//circle'
+  )
+  length(nodes)
+}
+
+# ----------- TESTS -----------
+
+test_that("Render animation correctly", {
+  expect_true(!is.null(info))
+})
+
+test_that("HTML contains SVG", {
+  expect_true(grepl("<svg", saveXML(getHTML())))
+})
+
+test_that("Plot title exists", {
+  expect_true(grepl("Bisection Method Animation", saveXML(getHTML())))
+})
+
+# ----------- INTERACTIVE TESTS -----------
+
+test_that("Initial midpoint visible at iteration 1", {
+  count <- get_point_count()
+  cat(sprintf("Result: %d point(s) visible\n", count))
+  expect_equal(count, 1)
+})
+
+test_that("showSelected: switching to iteration 5 still shows 1 midpoint", {
+  clickID("iteration___5")
+  Sys.sleep(5)
+  count <- get_point_count()
+  cat(sprintf("Result: %d point(s) visible\n", count))
+  expect_equal(count, 1)
+})
+
+test_that("clickSelects: deselecting a side hides that midpoint", {
+  # reset to iteration 1 first
+  clickID("iteration___1")
+  Sys.sleep(3)
+
+  before <- get_point_count()
+  cat(sprintf("Before deselect: %d point(s)\n", before))
+
+  # The midpoint at iteration 1 is on the "right" side — deselect it
+  clickID("plot_bisectionPlot_side_variable_right")
+  Sys.sleep(5)
+
+  after <- get_point_count()
+  cat(sprintf("After deselect: %d point(s)\n", after))
+  expect_equal(after, 0)
+})